Q words without U
There are exactly 26 U tiles in a standard tile set and one Q, so holding the Q without a U is not an unlucky edge case — it is a normal Tuesday. The whole solution is this list. It is 29 words long, which is short enough that there is no real excuse for not knowing the useful half of it.
The three to memorize
If you learn nothing else here, learn qat, qoph and suq. Qat is a shrub whose leaves are chewed as a stimulant, qoph is a Hebrew letter, and suq is a North African marketplace. All three are short, all three are accepted in essentially every game that uses this dictionary, and each pluralizes with a plain S. Between them they cover almost every board position a stranded Q can reach.
The rest of the list
Most of the remainder are loanwords: qanat (an irrigation tunnel), qintar and qindar (Albanian currency), sheqel (Israeli currency, with the irregular plural sheqalim), faqir (a variant of fakir), qiviut (musk ox wool) and umiaq (an Inuit boat). Two are modern: tranq and qwerty.
The one to be careful with is qwerty. It is in this dictionary, but plenty of games treat it as a proper noun and reject it — worth knowing before you stake a turn on it.
The complete list
3 letters
4 letters
5 letters
6 letters
7 letters
8 letters
Holding a Q right now? Type your rack into the unscrambler — it will show which of these you can actually play, along with everything else your letters make.