2. Drawing upon DnD's schools of magic, you already have Enchantment and Transmutation. I think the most interesting would be Abjuration, runes which produce non-physical, protective and warding effects. The obvious application can be like magic barriers, but maybe it can do like a zone of truth, or a rain caller, or rain-go-away-er. Maybe like a rune-disabling rune?
3. Ignoring the magical consequences and drawbacks, let's talk about people. One thing I've seen is magic tattoos. Though yeah humans already have sentience, Cognition, Movement and Sentient runes don't grant much, but they could perhaps further enhance human aspects.
You can use a movement rune on your fist, so when activated can give even more speed to your punches, or on your legs to run faster. I guess you could use a stronger rune to move your entire body, so you have a quick movement option. Also environmentally-friendly cars
Cognition (or maybe Sentience?) runes can potentially specialize someone's knowledge, so you can have a person who knows everything about cooking, but less about history.
Enhancement runes don't have very diverse applications. I guess you can enhance your fist hardness for, well, harder punches. You can enhance your legs to withstand higher drops, or maybe your bones. Runescribe on your bones??? That's an idea.
How about Transformation runes on their body. Turn your fist into steel for harder punches (please don't mind my insistence on punching haha). Turn all your bones into steel so they're much better in combat, at the expense of blood health? Maybe the more extreme people can transform into other animal parts. Turn your left arm into a bear arm. Turn your teeth into a snake's fangs. Turn your eye into a cyborg laser eye. Unless Transformation only affects the material, and not more complex concepts. In which case just turn your bones into steel, you probably don't need that bone marrow anyways.
Then there's offensive applications. Movement Rune a guy backwards away from you, or towards your waiting spear. Cognitive Rune a guy into not knowing anything? Remove their knowledge? If you can do like reverse Enhancements, make a guy's arm into mush so they punch like a soggy bagel. Transform a guy's leg into air. Transform the whole guy into air while you're at it. Or at that point gold for profit. That's a villain idea right there, kidnapping people and Transforming them into valuable resources.