There are many interesting mods that lack decent graphics.

It would be cool if you could agree and make individual sprites for mods:

Krastorio 2 - nuclear locomotive https://mods.factorio.com/mod/Krastorio2
Krastorio 2 - Additional Locomotives - fusion and anti-material locomotive https://mods.factorio.com/mod/Krastorio2-more-locomotives
Diesel Trains - diesel locomotive https://mods.factorio.com/query/Diesel%20Trains?version=1.1
Battery-Electric Train - battery locomotive https://mods.factorio.com/mod/BatteryElectricTrain

And then the vanilla sprites here look somehow unnatural and boring.

There are a couple more transport mods - where the sprites are outdated:
Turbo bike https://mods.factorio.com/mod/TurboBike
Heavy Truck https://mods.factorio.com/mod/bigtruck - there the truck is quite small - you can try to negotiate, or make a fork with new larger sprites

Same with mods:
Aircraft https://mods.factorio.com/mod/Aircraft
Better Cargo Planes https://mods.factorio.com/mod/betterCargoPlanes
Space Shuttle https://mods.factorio.com/query/Space%20Shuttle?version=1.1

There are all the same sprites plus small airplanes, it would be possible to add variety and make larger versions.

Have you tried angel's addons for locomotive? It's a standalone mod which have 3 models for trains. Looks good too. But I agree on nuclear locomotive. Wished it looked better.

Angel trains look cool! But in fact, these are just thematic skins of an ordinary solid fuel locomotive.

YuokiTani has no less interesting sprites. True, I did not manage to launch it in conjunction with Krastorio 2 + Space exploration.

I noted those mods where locomotives with completely different types of energy and engines are implemented, which, due to their logistical and technological features, will diversify the gameplay, and it would be natural for them to add individual skins that distinguish them from a regular locomotive.

Sacredanarchy wrote that he loves making sprites for mods. So, I've listed a few interesting mods that lack good, varied sprites.

Ive made a motorbike mod instead of reskinning the other one.

Thanks! This is also a good option.

Motorcycles are awesome!