Does anyone know of a really good fabric glue, for use on DIY projects

i think Alene's Tacky glue works great - it dries flexible instead of cracking and is nice and thick.

Aeillens makes a good glue

Mod Podge

Alene's, Mod Podge and white Elmers are all water based glued that work great on fabrics. Even the cheapo "white school glue" works.

These thin with water and are easily applied with a paint brush. Keep it fairly thick but spreadable on the entire fabric and then apply fabric to your item. Smooth it down flat and reposition if necessary. Clean up with a damp wash cloth.

All of these glues are similar (latex) and dry clear with some flexibility. They are easy clean up and do not smell. I use them all, Modge Podge is one of the best but cost more. (These glues can be intermixed.)

Aleene's Fabric Fusion is my favorite. It's great for just fabric to fabric, or for adding embellishments like sequins or beads.

All Alene's glues are my favorites. Available at most craft stores and Walmart.

I always use Alene's.

I use Aleenes's. https://www.amazon.com/Aleenes-Fabric-Fusion-Permanent-Adhesive/dp/B00178QSE6

Arlene's brand...I use it all the time. Get at Michael's

Oops, Aleenes...