With the recent complaints about X-wing being a tad weak, a popular suggestion is adding more Astromechs. Even if you think the X-wing is fine, you've got to admit the Astro-slot is just a sub-par System/crew Slot at best. Sure A2 and D2 are great, but most of the others are situational, only good on a particular pilot (R7 cough cough), or just straight up bad (K6).
However, the thing I love about droids is that they work best on their thematic partner (Luke doges well, D2 regens what he can't, Porkins Can't Hold It, D8 Holds It). So let's take a look at the Pilots we have, and we if we can't think of thematic droids to go with em.
First six members of Red Squadron and their droids (at the time of Yavin. Droids we don't have are bold):
1) Garven Dreis - R5-K6. This should work in theory (Garven focusing, K6 keeping him TLed) but Green Dice
2) Wedge Antilles - R2-A3. (probably should boost offense or something)
3) Biggs Darklighter - R2-Q2. (defense. Maybe something like Jan Crew?)
4) John D. Branon - R4-M9. (we don't have a pilot for this guy, and tbh all he does is say 'im hit' and die)
5) Luke Skywalker - R2-D2. Luke dodges, D2 gives him shields. PB and Chocolate.
6) Jek Porkins - R5-D8. Not the best, as it requires you to roll a greenie, but with Hull + Push, and provided you aren't constantly trying to Hold It, you should be ok.
Other named pilots with droids:
Corran Horn - 'Whistler'. (Wookiepedia: "Whistler was programmed by Cor-Sec with an enhanced sensor package..." Presumably the opposite of Whisper)
Probably some other droids, but I can't find them.