The site above has been kindly created by a fellow steemian providing a list of bid-based voting bots with all the info you need on them to place a profitable bid. Furthermore, it also lists information on content promotion services including MinnowBooster, RandoWhale and more. Lastly it also has a list of other bots that may be useful to you.
If you have ever used a voting bot and been unprofitable, or are keen to know of other voting bots that are available then please check out the website above!
Happy holidays and may your steem posts prosper!!!