Codeable
If you are looking for a curated set of professionals then Codeable is the ideal place for you. With over 60,179 projects completed and a 98.9% 5 out of 5 star rating, it is most definitely worth your time.
The skilled experts will listen to your requirements and place an estimate to help you with your project. Click here to check out Codeable.
SuitePlugins
Here at SuitePlugins, we also offer custom work for Ultimate Member projects. We take pride in having a profound knowledge of the plugin and can help with Consultations and Custom Work for our project. Contact us to get some help.
Other sites
UpWork
This site has been around for a while and has 1000’s of developers. However, we were unable to find Ultimate Member specific developers but perhaps your may have better luck.