I really like the way Alt Art cards have been done on a few choice upgrades. Leading Shots and Xi7 feel close to staple cards or at least cards you would buy (and probally have ) one ship to get the card.
I think a good choice would be Flight Controllers. It comes in the somewhat still expensive VSD expansion, despite being released a while ago. It's great for either faction and given the prior alt art cards were faction and ship specific Flight Controllers fits the bill. It is also somewhat collectible because unless you bought heavily into Wave 1/Imperial it's not a card you probably have multiples of. Given Floatila carriers, the prevelence of squadrons and still emgering archtypes (Reeiken heroes etc) this all points squadrons having a place now and in the future.
I find it is the most sought after loan card because once the meta shifts to squadrons lots of people want this.
Cheers.
Edited by Trizzo2