autobumper.io makes automated posting on forums really easy. By coupling an existing forum account from a specific forum or community, we can create a post as if it was sent from a regular browser session. Also, it's totally undetectable!Read more here
TRiBot is the world's most popular RuneScape® bot. It is easy to use, extremely efficient, and has tons of scripts. Supports Old-School and RS3.
Their forums contain a variety of categories including a big market section focused around RuneScape virtual items and related services.