Midnight Oil

If Midnight Oil has no hour counters on it, its first triggered ability will continue to trigger and have you draw an additional card, even though you can't remove any counters from it.

If multiple effects try to set your maximum hand size to a certain number or state that you have no maximum hand size, the one created latest is the one that applies.

If you discard a card during your cleanup step while you control Midnight Oil, its last ability will trigger, and players will get priority in your cleanup step. You'll have another cleanup step after that one before continuing to the next player's turn.