I require list of forums that allow do-follow signature and are in the niches of Webmasters, SEO, Internet Marketing, Social Media, PPC, Web Hosting, Android & iOS Apps and related topics. Make sure when suggesting this that these forums allow do-follow signatures presently.
Your best bet is to use footprint searches on Google to find them. I'll attach a massive list for you to help you out... You may also use sites like DROPMYLINK.com that have the footprints built in.