Any wrapped furniture item worth 7500 bells will give you the maximum friendship. If you’re working towards getting all the villager photos (my personal goal) that’s one of the quickest ways. I believe wrapped fossils also achieve the same amount of points but I’m not sure. I make iron door hangers and wrap them and give them to every villager that I’m not level 5 friendship with yet. At level 5 there’s a chance they’ll give you their photo, but you can increase your odds by making sure they send their gift to you to your house. That requires a little more effort but if you’re curious I can explain.