You have no maximum hand size.

At the beginning of your upkeep exile the top card of your library.

{2}, {t}: Roll a d20.

1-9 | Return a random card exiled with Bag of Holding Things to your hand.

10-19 | Return a card exiled with Bag of Holding Things to your hand.

20 | Return all cards exiled with Bag of Holding Things to your hand.