Self seeded, my best guess is field maple.

Tricky to be accurate because they're new leaves, but from the number of secondary veins and the way the leaves curve, I'd guess something closer to sycamore.

Hello, I'm new to Bonsai and was recently given these two trees and I'm hoping that someone can help identify them, thanks:

The first one is an Olive, Olea Europea by the looks of it. I’ve been following this guide to the letter and have had fantastic results https://www.kaizenbonsai.com/bonsai-tre ... -as-bonsai

I think both your trees are reasonably good for beginners, as long as you keep them in full sunlight. The second one is crab apple, which is deciduous so you'll have the benefit of comparing one evergreen and the other deciduous. Both survive easily both in hot and cold conditions. Both like a lot of water, without leaving them in standing water.
The crabapple drinks tons, the olive can go a bit drier before watering. I'm surprised that there are still flowers on the crab apple. But I can see one small apple forming there too. Have fun!