What are some gambits for beginners?

Queen's gambit is the best because you can keep playing it till GM level. Of course at that level black will almost always decline the gambit. But Queen's Gambit Declined is still a good opening for white.

There are numerous attacking lines in Queens gambit, and here are three of the most basic ones:

If you are a 100 elo or some low rating player, you can do this simple gambit. It's called the Soller Gambit.

You can play Halloween gambit

I recommend the Evans Gambit. If you want something more spicy, try the Kings Gambit

Practicing using initiative and attacking with tactics is more important than memorizing many lines

Play like a drunken Hussar! Charge into the fray with the Danish and all its Gothic barbarian cousins --the Goring, Scotch, and Urusov gambits. Sack Rome and win eternal glory, or, like Custer, eat dust on a hill side in Montana.