Compliments don't have to relate to physical appearance. Although those can be nice to hear, there are countless other ways to pay the same kind of praise and these are often more gratifying to both say and hear than their outward counterparts. Here are a few of them.
1. I love your style/ aesthetic.
Okay, admittedly this is along the same lines as outward appearance, but it isn't the classic "wow, you're so beautiful". Admiring someone's aesthetic can be significantly different than thinking they are classically beautiful, and to recognize such a thing is to recognize the effort that they place into how they present themselves, not just their facial structure or body shape.
2. I feel like I can really rely on you.
Unless whomever you are complimenting is hiding something terrible from you, this is another great way to perk up someone's day. Knowing that someone wants you in their corner implies trust and just straight up friendship.
3. You make me laugh harder than anyone else I know.
Obviously only say this if it is true, but anyone who even attempts to be funny and manages to succeed would love to hear that they make your day brighter.
4. You make my day(s) brighter.
This feels self explanatory. You would be expressing your gladness and happiness at their mere existence, which is pretty awesome.
5. I am so glad you are a part of my life/ that I met you.
Perhaps this is one of the most important on this non-exhaustive list. Anything else so far outlined can be assumed, implied, showed in various ways, but this is one that anyone will love to hear. Your mom? She wants to hear that you genuinely appreciate the support and love she gives you. Your best friend? He sometimes questions this, he worries that maybe you don't like him as much as he thinks you do or that sometimes he annoys you. Tell the people you care about that you are glad you have them.
6. I like talking to you.
Assurance that the time spent with this person is something you value. Saying that they give good advice can accomplish something similar to this as well, though has a different resounding feeling.
7. You/ your (insert aspect, such as laugh) makes me happy.
Again, just the assurance and appreciative nature of such a statement is strong. To give joy to someone is love, but to say that you enjoy their love as well? Perfect.
finally, my favorite...
8. You are good.
I find this being simple, but it says it. To me, this says everything that it needs to. You see this person as kind, as loving and gentle and what you needed them to be. They are good.
Love you friends, love your family, love each other. Show your love in ways that mean more than bodies, more than physicality, more than looks. Love.
