Is there a Latin phrase similar to the English "well done!" to be used to congratulate someone for achieving something? Translating from English, one might expect bene factum! or bene fecisti! or something similar, or just a plain adverb (bene!, egregie!, optime!...), but I have never encountered any such thing in use. Is there a set phrase for this purpose?
“macte virtute esto” sanguinolentis ex acie redeuntibus dicitur
it is to the blood-stained soldier returning from the front that men cry: “Well done!”
Seneca the Younger, Epistles, 66
‘Oratorem’ legas? macte virtute!
You're reading The Orator? Well done!
Cicero, Letters to Atticus, 243 (XII.6a)
In questions of spoken Latin, Plautus is my go-to. One good term for this, frequent in Plautus, is euge, from the Greek εὖγε. A corpus search reveals quite a few examples, often with native Latin repetitions:
Euge euge, lepide, laudo commentum tuom. (Miles Gloriosus)
Euge, euge, exornatu's basilice; (Persa)
There are many other excellent choices, but I'll leave those for other answers.