Asking for links to online sources is something that I think is frowned upon at our Main site too. From the sounds of it I know that I am very likely to vote to close such a post for being too broad.
If you are having difficulty developing plugins for QGIS, then you could ask questions on Main about those specific difficulties, because such focussed Q&A is always welcome.
If anyone reads your focussed questions there and knows an online source that might short circuit future similar questions then I am sure that they will mention it in a comment or answer.
The GIS Chat Room is the only part of GIS SE where I think asking for links to sources is OK to do, but I think asking focussed Q&A questions on Main offers a better chance of uncovering what you are after.