Here's a quick DIY recommendation: book tape.
Libraries and other bibliophiles rely on this sort of tape to make repairs and keep spines happy. (Book spines, that is . . . I'm still working on my own long-suffering bony counterpart.) Of course, book tape works great on books, but I've been most interested in it for its "off label" applications.
As a crafter, one use I've found for book tape has been as a sturdy "hinge" on paper goods. If I'm making (say) a box or binder with a fold that I want to ensure can withstand a lot of wear, some book tape at the fold on both faces of the material works wonders. In fact, I've even joined separate unconnected items to form a more-than-usable larger construction. For example, if I take three magazine boards (printed or plain) and affix them together with book tape, then I suddenly have a quite-usable GM or player screen for my favorite game.
Of course, book tape is incredibly helpful for a long-lasting, acid-free repair mechanism for a game box you accidentally stepped on because you failed to pick it up off the living-room floor. Hypothetically.
Book tape is not without its disadvantages. Most notably, it's opaque (at least the cloth stuff I favor), and is obviously a strip of tape. I like that aesthetic, but I can imagine how others might want something that looks a bit cleaner or less obvious Still, it's a recommendation I wish I'd had about a decade before I discovered it.
Here's a link to the roll I purchased most recently. I like this particular brand, but my search has not been exhaustive. I encourage you to experiment and find what works for you. If you do find a method or product that you like, please feel free to share your recommendations on the forums!
-- Steven Marsh