I recently found out that Racktime makes little snap-on bracks that let me turn anything I can drill holes in into snap-on modules for my bike.
The Bike is a rental so it took some time to figure out how to add a rear rack so that I can take it off if I need to return it but I am incredibly happy with the results!
Damn that thing is ready to haul 💪
Thanks for mentioning the brackets - I’ve been on the lookout for various DIY ways to attach stuff to my pannier rack
Defintly check out the SNAPIT 2.0 CONNECT you can make any rack compatible with the snapit system :P
What I used to connect the Ikea shelf and a random suitcase is the SNAPIT 2.0 SYSTEM ADAPTER