1. Junior officer appreciation:
-Talk to the Doff person at the academies, Lieutenant Ferra or S’stas. This gets you two things, first is a 50% cxp bonus that lasts all weekend. Second is you can get a special purple doff. Feds get an exocomp, klingons get a reman.
-C-store doff packs when opened spawn an extra green doff.
2. Fleet support doff packs:
-they're being discontinued in about 2 weeks
-They're currently 15% off
-Between now and when they're discontinued, each one you open will provide 10 lobi crystals or a Jem attack ship (bug). This is in addition to their normal rewards.
The fleet support doffs (like consultants) will probably come back via mini-packs in some upcoming lockbox, but this is one of the rare-ish chances to get a jem attack ship.
Also, you should run and grab that special purple while you can. They're a maintenance engineer with a special power, when you use a battery it gives you a special bonus (depending on the type of battery used).