Extra
Supplementary
Synonyms: Additional, added, supplemental, auxiliary, subsidiary, attendant, other, new, more, supplementary, further, ancillary, secondary, accessory, another, and fresh.
Specially
Synonyms: Exceptionally, specially, very, singularly, distinctly, extraordinarily, uniquely, strikingly, amazingly, awfully, really, notably, decidedly, conspicuously, seriously, mucho, dead, devilish, powerful, particularly, especially, extremely, peculiarly, unusually, uncommonly, remarkably, outstandingly, incredibly, terribly, unwontedly, markedly, surprisingly, signally, majorly, jolly, well, frightfully, and right.
Additionally
Synonyms: In addition, as well, too, over and above that, further, to boot, again, withal, additionally, also, besides, on top (of that), into the bargain, then, furthermore, and forbye.
Addendum
Synonyms: Addition, adjunct, add-on, accompaniment, companion, extension, accessory, retrofit, supplement, addendum, bonus, complement, additive, appendage, attachment, and peripheral.
Supernumerary
Synonyms: Walk-on, spear carrier, minor role, bit part, NPC, supernumerary, walk-on part, non-speaking role, nonplayer character, and redshirt.
Example Sentences
She brought an extra sweater.
We have extra time today.
He added extra cheese toppings.
The meal includes extra dessert.