This is a great question, and I’m sure you’re not the only person wondering the same thing! Something my S/O and I have been doing for gifts recently is making “Open When” letters. Basically, they’re a stack of letters, and each of them have a different purpose. They each say “Open when you feel…” and have a different emotion assigned to them. You can make one for bored, sad, missing each other, happy, etc. They’re really fun and heartfelt and cost almost nothing! You can attach rules to them, too, like how many you’re allowed to open a week, or you have to be on the phone to open them, etc. Just have fun with them!
There’s also the classic chocolate, flowers, stuffed animals, etc. Those can be a great simple way to tell your S/O you love them. You could try getting them a bunch of small gifts with a theme to show that you know what they like or remember the little things. I once got my S/O a tea-themed gift, with a mug, a bunch of their favorite tea bags, and a little tea strainer, so you could try something like that. You could also do a color theme, or a music theme, etc. There are tons of options! The important thing to remember is that a really good S/O will love you no matter what, even if you aren’t super good at gifts. Good luck!