These are not unique to my agency; but are probably rarely used by those outside some incarnation of the budget and finance community. Only including a few so as not to bore everyone 😉 :

ATB = Across-the-Board (which in and of itself is generally shorthand for an across-the-board reduction or an across-the-board recission) [of funds]

EOFY = End of Fiscal Year

PB = President’s Budget

ADA = Anti-Deficiency Act