I went to an exotic tree nursery out of town and saw a large tree planted in the ground with some fruit. I asked the caretaker what it was but I don't recall what he said. I think it was white sapote though. He gave me a fruit that had fallen and I ate it once I got home. It was delicious so I planted the seeds. I googled "white sapote" but the fruits do not resemble what I had in shape. The googled pics were all round but the fruit I had was kind of mango or kidney shaped. Does white sapote come in this shape? If so what would the variety be.

Unfortunately, I did not take a picture of the fruit or seeds but the flesh of mine looked similar to the pics of white sapote that I found

Unfortunately, the word "sapote" is used for several fruits in different plant families. You might google photos of white, black, green, and mamey sapotes, as well as sapodilla, to see if any of them resemble your fruit.

Do you remember what the seeds looked like? Pulp color? peel color?

If none of the above look promising, you might also search canistel and mammee apple.

White Sapote has several varieties around here, some round, some long.
You say "seeds", but generally seems to be one or two large seed per fruit, that sort of looks like a giant Citrus seed. The flesh is a bit like soft sweeter watery avocado, white or greenish underneath a thin light green skin.
Most of the Sapotaceae seed are dark brown/black, and look different to White Sapote seed.
Unless you have a true rare fruit, it should be easy to image search the list Dr Manners wrote to find what you have.

I think the guy said white sapote. It was long, had a lime green skin color and a pale yellow flesh that resembled the texture of avocado. There were three seeds, one of which was undersized and the color was yellowish beige. It appeared to have sort of a husk around it but I didn't peel it off before planting.

That all sounds very much like a white sapote.

Thanks. Any idea of what variety it might be? This being oblong, all of the pics I've seen were round.

I planted the seed and it sprouted a few weeks ago. There is more than one sprout though. What's the best way to go? Keep them all growing in their present position and have multiple trunks? Or keep the tallest one and cut the other ones down? Or separate and grow as individual trees? By the way, I plan to keep these in pots.