Here are some representative samples of custom modules I have created.

Node usage: displays every content type in use and the number of of instances of each node (this is a contrib module you may download at https://www.drupal.org/project/node_usage).

Site: utilities and themed custom blocks (for this site).

Pet guides: a support module for a custom content type that loads css and display template (for a different site).

Attachment Size
Node usage (7.x version) 2.7 KB
Node usage (8.x/9.x version) 4.27 KB
Site (9.x) 8.28 KB
Pet guides (9.x) 11.5 KB