I want to link homebrew items into my homebrew monsters. The only problem is that I can create an item very easily, but I can't figure out how to add them to my monster. I can link existing/official items into my homebrew monsters, just not my homebrew items, or abilities. Any suggestions?

Those special links are calls “tooltips” and they don’t work for homebrew content without pseudo-hacking them.

Well that kinda sucks...thought that might be the case. Thanks though.

Those tool tips are easy for official stuff because there’s only 1 of everything in the system. If we both type Longsword, +1 the system knows what we mean. If we both name an item the same thing, thy system won’t know which one we mean without that I’d code.

One solution is to select the raw text that is referring to the homebrew item you want to reference, and use ctrl+k to insert an external link (note, this will also prevent you from sharing your original homebrew monster to the dndbeyond community).  Then you copy the url link of you homebrew item into the url section of the popup dialogue box, and you'll have a usable link (note: the link will not have a mouse-over summary, but will instead open the homebrew item in the current tab).

General FAQ #9:

https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq