however, yet, still, though, furthermore, nevertheless, moreover, although, albeit.

only, excluding, save, further, only if, with the exception of, plainly, provided, tho, nevertheless, scarcely, otherwise than, notwithstanding, exclusively, except, solely, unless, just now, purely, just, yet, barely, moreover, scarce, entirely, exactly, without, just, exclusive of something, still, and, aside from, merely, excepting, include, only, alone, merely, simply, only when, besides, that, beyond, precisely, hardly, however.

But I do not know you. - "Historical Romances: Under the Red Robe, Count Hannibal, A Gentleman of France", Stanley J. Weyman.

But you don't mean it, do you? - "The White Peacock", D. H. (David Herbert) Lawrence.

But the Delhi Vase! - "Sweethearts at Home", S. R. Crockett.

but then, last but not least, butt, butt against, butt end, butt in, butt joint, butt on, flash butt welding.