Trixter
anasuya.com
Known as "Stich Ansagen" in Central Europe, which roughly translates to "Predict Tricks" or "Call the Trick". Play is from 1 to 13 to 1 card hands and even bidding is allowed.
Oh Hell
en.wikipedia.org
Game overview from Wikipedia.
Oh Hell: Results and Stats
cs.utk.edu
Offers software for tracking statistics, and the results for a group of regular players.
Romanian Whist
pagat.com
In this variation of Oh Hell, extra hands are played with one card and with the maximum cards, even bids are disallowed, and points are lost for missed bids.
Oh Hell!
geocities.com
The rules as played at the annual Cartier Oh Hell Championship in London, England.
Blackout
gamerz.net
Rules for this variant. Offers play-by-email.
Love That Joker
pagat.com
This variation adds two jokers to the deck which at as wild cards. Either joker can be played as being of higher rank than the Ace of any suit, or lower than the 2, at the player's discretion.
The Rules of Oh Hell
home.cshore.com
Pratt and Whitney East Hartford Cafeteria Card Players' Club variation.
Oh, Hell, Culver City Style
gg.caltech.edu
This variant plays hand size from 4 to 13 cards, high bidder names trump, point loss for missing your bid, and even bids are not allowed.
Oh Hell!
zechiel.com
Al Okenuff's rules where you lose points if you do not make your bid.
Oh Hell!
pagat.com
Pagat.com provides rules, variants, score sheets, related games, and links.