Index: wp-admin/css/list-tables.css
===================================================================
--- wp-admin/css/list-tables.css	(revision 43725)
+++ wp-admin/css/list-tables.css	(working copy)
@@ -1413,6 +1413,15 @@
 		margin-right: 8px;
 	}
 
+	.plugin-card:nth-child(3n+1) {
+		clear: none;
+		margin-left: 8px;
+	}
+
+	.plugin-card:nth-child(3n) {
+		margin-right: 8px;
+	}
+
 	.plugin-card:nth-child(4n+1) {
 		clear: both;
 		margin-left: 0;