All the aliens identified on this concept art for Ben 10 Alien Force : r/ Ben10

Ben10 Alien Force Fanart By Nefta3007 : r/Ben10

I Drew the Alien Force Aliens : r/Ben10

Ben 10 Alien Force (Redesign) by Fiqllency on DeviantArt

The first 50 proper transformations (canon and fan-made) I have drawn for my Instagram account. : r/Ben10

ArtStation - BEN 10 Redesign - All the Aliens (classic)

ArtStation - Ben 10 Alien Force - Redesign Aliens

Alien Force x Omniverse art : r/Ben10

Ben 10: Alien Force (Pre-Production), Ben 10 Wiki

Every Ben 10 OS alien on Pixel Art by me. : r/Ben10

If the entirety of Ben 10 had the art direction/designs of the OS with the more mature tone of UAF and the world building of OV, it would've made the perfect franchise.

ArtStation - BEN 10 Redesign - All the Aliens (classic)

Original Ben 10 series fan art (10 original aliens illustrated + main characters) : r/fanart

Crew's Unofficial Artwork, Ben 10 Wiki