The ACK-256 by Creative Fibs purported to have 256 voice polyphony (although most endusers misinterpreted the 256 as referring to bit resolution and therefore much talk ensued in comp.sys.ibm.pc.soundcard.tech as to how 256-bit audio was much better than crummy 16-bit audio). This polyphony was accomplished via the card's software driver, which did a cheesy FFT on the digital audio and counted each "overtone" as a separate voice. In reality, the card sported the same 8-bit mono CODEC as its earlier sibling, the Creative Fibs' Sound Masher Deluxe Game Pro Value Edition.
The Pitiful by Beached Turtle was renowned for its very frustrating installation and setup. The only way that its proprietary "inhumane hardware" design would not conflict with Windows 95 or NT virtual memory is if one disabled all of his motherboard RAM before booting.
The Afix by ICM would have been a best selling card in 1996 except for one fatal flaw -- it never made it to market. Contrary to the company's name (pronounced "I see 'em"), nobody ever did see one of them. The card never made it out of the lab as ICM forever revised its specifications and design in an attempt to "fix" problems with its W.A.S.T.E. synth chip -- whose MIDI implementation was so secret that nobody knew what to do with it and ended up not using it for much.
A noisy output on this card inspired endusers to quip "Yermama" jokes about this card such as "Yer sound card's S/N ratio is so UGLY, it scares pink noise white".
The Sour Trix Pro by MarketingTrix would have sold well except that its $300 pricetag, plus $100 for the sampling board, plus $150 for the wavetable board, plus $100 for the digital I/O board, plus $50 for the screws to secure it into an ISA slot, was too much for most consumers' budgets.
The Ulcer Sound by Advanced Gaseous (a company which tended to periodically vanish into thin air) gave plenty of folks a stomach ache as they tried to obtain working drivers and other support for this oddball game card. The most renowned aspect of this card was that it pioneered "Wavetable instrument loading", a technique for replacing an utterly disgusting waveform set in ROM with really expensive, hard-to-find SIMM chips.
NOTE TO LAWYERS WORKING FOR CERTAIN SOUND CARD COMPANIES: Don't bother suing me. I have no money. I spent it all on MIDI and computer stuff.