So thinking up some card abilities that would work as counters to Palpatine, and came up with the below options for a Yoda Crew card. Part of the challenge is something that works against Palp but can be used against other lists, too. Admittedly, some of these may be broken -- which ones are viable and what should they cost.
Yoda (Crew, Rebel only, ?? Points)
1. Once per round, when attacking or defending, after your opponent modifies dice, you may change one die back to its original facing. (This one is a direct counter, but works against focus and target locks, too.)
2. Once per round during the combat phase, when your opponent uses an ability on an upgrade card, you may cancel the use of that upgrade. If the ability required the card to be discarded, it is not discarded. (Do, or do not, there is no try. Probably over powered, so ...)
3. When your opponent uses an ability on an equipped upgrade card, you may discard this card to cancel that use. If the use required the upgrade to be discarded, it is retained.
4. Once per round, when your opponent uses a pilot ability, you may negate the use of that ability. (Not a direct counter, but counter-thinking. Almost certainly broken as written, so ...)
5. When your opponent uses a pilot ability, you may discard this card to negate the use of that ability.
6. At the start of the first round, discard this card to select one of your opponent's upgrade cards. The opponent must immediately discard that card.
7. Once per round while attacking or defending, if your opponent modifies a die without spending a token, you may also change one of your dice to any result. (Mine! Or I will help you not!)
8. When the ship equipped with this card is destroyed, select one of your opponent's upgrade cards. Your opponent must immediately discard that card. (Yoda takes one of your toys with him to exile on Dagobah.)