Bought uber, airbnb and reddit in 2018 on equidate/forgeglobal.

Structured as contracts for future stock from current employees that get transferred to you after the ipo (and usually 6 month lockup) are complete.

I got 100% of the uber stock (about 1x return) about 99.8% of the airbnb (about 2.5x return) and depending on if/when reddit ipos (was looking good for 10x a few months back but unlikely now) it will be interesting to see how much of the stock i get if it has gone up massively since initial purchase.