İlk istediğiniz için;
<?php
add_action('widgets_init', 'themeloy_register_widgets_grid_list');

function themeloy_register_widgets_grid_list() {
    register_widget('themeloy_recent_posts_widget_grid_list');
}

class themeloy_recent_posts_widget_grid_list extends WP_Widget {

/*-----------------------------------------------------------------------------------*/
/*	Widget Setup
/*-----------------------------------------------------------------------------------*/

    function __construct() {
        $widget_ops = array(
            'classname' => 'cat_recent_entries clearfix',
            'description' => __('Ekran ızgara veya ön sayfada bir veya birden fazla kategoriden gelen son mesajları listeler.', 'tl_back')
        );
        parent::__construct('custom-recent-posts-grid-list', __('Klavyer: Ana Sayfa Bileşeni NO:1', 'tl_back'), $widget_ops);
    }

/*-----------------------------------------------------------------------------------*/
/*	Display Widget
/*-----------------------------------------------------------------------------------*/

    function widget($args, $instance) {

        extract($args);

        $title = apply_filters('widget_title', empty($instance['title']) ? 'Recent Posts' : $instance['title'], $instance, $this->id_base);
    
        $show_style_1 = isset($instance['show_style_1']) ? $instance['show_style_1'] : false;
		
        if (!$number = absint($instance['number']))
            $number = 4;

        if (!$cats = $instance["cats"])
            $cats = '';

        // array to call recent posts.

        $themeloy_args = array(
            'showposts' => $number,
            'category__in' => $cats,
        );

        $themeloy_widget = null;
        $themeloy_widget = new WP_Query($themeloy_args);

        echo $before_widget;

        // Widget title

        echo $before_title;
        echo $instance["title"];
        echo $after_title;

        // Post list in widget
		
		 $blog_date_widget = of_get_option('blog_date_widget', 0); 
		 $blog_comment_widget = of_get_option('blog_comment_widget', 0);


        $i = 0;

        while ($themeloy_widget->have_posts()) {
            $themeloy_widget->the_post();
            $i++;

				$thumb = get_post_thumbnail_id(get_the_ID());
                if (!$thumb) {
                    $url[0] = get_template_directory_uri() . '/img/demo/dum-2.jpg';
                }else{
					 $url = wp_get_attachment_image_src( $thumb , '177x100');
				}
					
                    
                    $date = '<span class="date">' . get_the_date('M d, Y') . '</span>';
                    ?>
                    <div class="small-feature">
					<div id="klavyer-icon">
                       <a href="<?php the_permalink(); ?>" class="feature-link"><img src="<?php echo $url[0]; ?>" alt="<?php the_title(); ?>"  />
                        <?php echo themeloy_post_type(); ?>
						<span class="goster-1-2"></span>
					</div>
                        </a>
                        <div class="feature-text">
                            <div class="post-title"><h4><a class="title" href="<?php the_permalink(); ?>" rel="bookmark" title="<?php the_title_attribute(); ?>">
							<?php echo themeloy_short_title(50, get_the_title('')); ?>
                            </a></h4>
                            </div>
                             <?php if($blog_date_widget == 0) { ?>
									<?php } ?>
                                    	<?php if($blog_comment_widget == 0) { ?><?php } ?>
                     <?php $enable_review = get_post_custom_values('reviewthemeloy_checkbox', get_the_ID()); ?>
	                 <?php if (of_get_option('disable_review') == 0){
						if($enable_review[0] == 1){?>
                     <span class="review-star">
                          <span style="width:<?php echo themeloy_get_total_review(get_the_ID()); ?>%" class="review-star-inline"></span>
                     </span>
                    <?php }else{?>
						 <span class="review-star-none">
                          <span class="review-star-inline-none"></span>
                     </span>
						<?php }}else{?>
						 <span class="review-star-none">
                          <span class="review-star-inline-none"></span>
                     </span>
                    	<?php } ?>
                        </div>
                       
						<?php
							foreach((get_the_category()) as $category) {
								$cikti = $category->slug;
							}

						?>
					   <div class="isim-d-<?php echo $cikti; ?>"></div><div class="isim-<?php echo $cikti; ?>"></div>
<div id="tarih-ana-alt">
<i class="post-meta-ic"><?php echo human_time_diff( get_the_time('U'), current_time('timestamp') ) . ' önce'; ?></i>
</div>
                    </div>


                <?php

            }
            ?>

        </div>  
      
        <?php
        wp_reset_query();


        echo $after_widget;
    }

/*-----------------------------------------------------------------------------------*/
/*	Update Widget
/*-----------------------------------------------------------------------------------*/

    function update($new_instance, $old_instance) {
        $instance = $old_instance;
        $instance['title'] = strip_tags($new_instance['title']);
        $instance['cats'] = $new_instance['cats'];
        $instance['number'] = absint($new_instance['number']);
     	$instance['show_style_1'] = (bool) $new_instance['show_style_1'];

        return $instance;
    }

/*-----------------------------------------------------------------------------------*/
/*	Widget Settings (Displays the widget settings controls on the widget panel)
/*-----------------------------------------------------------------------------------*/

    function form($instance) {
        $title = isset($instance['title']) ? esc_attr($instance['title']) : 'Recent Posts';
        $number = isset($instance['number']) ? absint($instance['number']) : 5;
        $show_style_1 = isset($instance['show_style_1']) ? (bool) $instance['show_style_1'] : false;
        ?>
        <p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:', 'tl_back'); ?></label>
            <input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo $title; ?>" /></p>

        
        <p><label for="<?php echo $this->get_field_id('number'); ?>"><?php _e('Number of posts to show:', 'tl_back'); ?></label>
            <input id="<?php echo $this->get_field_id('number'); ?>" name="<?php echo $this->get_field_name('number'); ?>" type="text" value="<?php echo $number; ?>" size="3" /></p>

<p><input class="checkbox" type="checkbox" <?php checked($show_style_1); ?> id="<?php echo $this->get_field_id('show_style_1'); ?>" name="<?php echo $this->get_field_name('show_style_1'); ?>" />
            <label for="<?php echo $this->get_field_id('show_style_1'); ?>"><?php _e('Display post feature below main post?', 'tl_back'); ?></label></p>
   <p>
            <label for="<?php echo $this->get_field_id('cats'); ?>"><?php _e('Select categories to include in the recent posts list:', 'tl_back'); ?> 

                <?php
                $categories = get_categories('hide_empty=0');
                echo "<br/>";
                foreach ($categories as $cat) {
                    $option = '<input type="checkbox" id="' . $this->get_field_id('cats') . '[]" name="' . $this->get_field_name('cats') . '[]"';
                    if (isset($instance['cats'])) {
                        foreach ($instance['cats'] as $cats) {
                            if ($cats == $cat->term_id) {
                                $option = $option . ' checked="checked"';
                            }
                        }
                    }
                    $option .= ' value="' . $cat->term_id . '" />';
                    $option .= '&nbsp;';
                    $option .= $cat->cat_name;
                    $option .= '<br />';
                    echo $option;
                }
                ?>
            </label>
        </p>

        <?php
    }

}
?>
2. istediğiniz widget için functions.php'nize şu kodları ekleyin;

class Yazi_ici_Benzer_Yazilar extends WP_Widget {

	function __construct() {
		parent::__construct(
			'yazi_ici_benzer_yazilar',
			'Yazı içinde benzer yazılar',
			array( 'description' => 'Yazı sayfasında benzer yazıları gösterir.(Etikete göre)', )
		);
	}

	public function widget( $args, $instance ) {
		global $post;
		$tags = wp_get_post_tags($post->ID);
		if(is_single() && $tags){
			$title = apply_filters( 'widget_title', $instance['title'] );
			$tag_ids = array();
			foreach($tags as $individual_tag) $tag_ids[] = $individual_tag->term_id;
			
			$args = array(
				'tag__in' => $tag_ids,
				'post__not_in' => array($post->ID),
				'showposts' => 4 // kaç tane gösterilsin
			);

			echo $args['before_widget'];
			if ( ! empty( $title ) ) {
				echo $args['before_title'] . $title . $args['after_title'];
			}

			echo '<div class="widget recent-posts">';
        	echo '<ul class="ulpost">';

			$my_query = new wp_query($args);
			if( $my_query->have_posts() ) {
				while ($my_query->have_posts()) {
					$my_query->the_post();
				?>
					<li>
							<div class="yazi-tarih"><div class="yazi-tarih-ic">
				<i class="icon-calendar"></i> 
				<i class="post-meta-ic"><?php echo human_time_diff( get_the_time('U'), current_time('timestamp') ) . ' önce yazıldı'; ?></i>
				</div></div>
                <?php
               	$thumb = get_post_thumbnail_id(get_the_ID());
                if (!$thumb) {
                    $url[0] = get_template_directory_uri() . '/img/demo/dum-6.jpg';
                }else{
					 $url = wp_get_attachment_image_src( $thumb , '300x170');
				}
				
				
                echo '
				<div id="klavyer-icon">
				<a class="entry-thumb2 feature-link" href="' . get_permalink() . '" title="' . the_title_attribute('echo=0') . '">
				<img src="' . $url[0] . '" alt="' . get_the_title() . '" />
				<span class="goster"></span>
				 </a>
				</div>
				
				
				';
				echo themeloy_post_type();
                ?>
             
                <div class="ulpost_title">
                    <a class="title" href="<?php the_permalink(); ?>" rel="bookmark" title="<?php the_title_attribute(); ?>">
					<?php echo themeloy_short_title(61, get_the_title('')); ?>
					</a>
                    <?php $enable_review = get_post_custom_values('reviewthemeloy_checkbox', get_the_ID()); ?>
	                 <?php if (of_get_option('disable_review') == 0){
						if($enable_review[0] == 1){?>
                     <span class="review-star">
                          <span style="width:<?php echo themeloy_get_total_review(get_the_ID()); ?>%" class="review-star-inline"></span>
                     </span>
                    <?php }else{?>
						 <span class="review-star-none">
                          <span class="review-star-inline-none"></span>
                     </span>
						<?php }}else{?>
						 <span class="review-star-none">
                          <span class="review-star-inline-none"></span>
                     </span>
                    	<?php } ?> 
						
						<?php
							foreach((get_the_category()) as $category) {
								$cikti = $category->slug;
							}

						?>
					   <div class="isim-d-<?php echo $cikti; ?>"></div><div class="isim-<?php echo $cikti; ?>"></div>
						
                </div>


            </li>
				<?php
				}
				wp_reset_query();

		        echo "</ul>\n";
				echo "</div>\n";
			}
			 
			echo $args['after_widget'];
		}
	}

	public function form( $instance ) {
		if ( isset( $instance[ 'title' ] ) ) {
			$title = $instance[ 'title' ];
		}
		else {
			$title = __( 'New title', 'text_domain' );
		}
		?>
		<p>
		<label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label> 
		<input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $title ); ?>">
		</p>
		<?php 
	}

	public function update( $new_instance, $old_instance ) {
		$instance = array();
		$instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';

		return $instance;
	}

} 

add_action( 'widgets_init', function(){
	register_widget( 'Yazi_ici_Benzer_Yazilar' );
});