Information

Minecraft: 1.20.2
Modloader: Fabric

Feature description

It's possible to spawn Minecarts with a custom block with an command. That's a wonderful mechanic which would be a huge plus in vanilla gameplay.

Holding a block, maybe with shift-right click, to put it into an empty Minecart. And getting it the same way out of the Minecart.

I took the first video link which showed up in the search results - it's a good reference:
https://www.youtube.com/watch?v=OP-v3sqA8Tg