Synonyms to double take

addendum, PS, Parthian shot, accession, accessory, accident, accidental, accompaniment, addenda, additament, addition, additive, additory, additum, adjunct, adjuvant, afterthought, annex, annexation, appanage, appendage, appendant, appendix, appurtenance, appurtenant, attachment, augment, augmentation, auxiliary, back matter, chorus, coda, codicil, collateral, colophon, complement, conclusion, concomitant, consequence, contingency, contingent, continuance, continuation, corollary, dying words, envoi, epilogue, extension, extra, extrapolation, fixture, follow-through, follow-up, happenstance, incidental, increase, increment, inessential, last words, mere chance, nonessential, not-self, offshoot, other, parting shot, pendant, peroration, postface, postfix, postlude, postscript, refrain, reinforcement, rider, second thought, secondary, sequel, sequela, sequelae, sequelant, sequent, sequitur, side effect, side issue, subscript, subsidiary, suffix, superaddition, supplement, swan song, tag, tailpiece, undergirding, unessential, about-face, afterthoughts, app