I finally used up the last of my stash, so lately I’ve just been buying a bunch of different leave-in conditioners to try. The best I’ve found so far is GIOVANNI 2chic Ultra-Luxurious Leave-In Conditioning & Styling Elixir. The product itself has a nearly identical look and consistency to the Neutrogena. It leaves my hair soft and smooth without looking greasy, and has very minimal hold. It isn’t stiff or sticky. It feels like it’s moisturizing my hair rather than drying it out.

My comments on a few others I’ve tried are below. I’m white with wavy hair that tends toward frizziness. My individual hair strands are fine, but I have a lot of hair, so anything too volumizing makes it into a poofball – but anything too heavy weighs it down and makes it look dirty (I usually can't use products intended for curly hair). I don’t blow-dry or do anything except comb in the leave-in conditioner and let it air dry.

1. GIOVANNI Eco Chic Direct Leave-In Weightless Moisture Conditioner, which I tried on the recommendation of u/Dependent_Low_2625 (thank you!) - This works okay but it’s a bit too thick and volumizing for my hair. I don’t love the somewhat sticky texture.
2. Living Proof No Frizz Leave-In Conditioner - I used to use this back in the day when my hair was much longer and more damaged. It really fights frizz, and the product itself has a similar consistency to the Neutrogena, although it makes my hair more flat than I would like. It’s good in humid or stormy weather.
3. Bumble & Bumble Styling Creme - I used this product for many years when my hair was longer and I wanted to enhance the waves. I feel like it dries out my hair a bit and can feel “crispy,” but it’s a good all-around product. It doesn’t create the smoothness I prefer now that my hair is much shorter.

Two more that I ordered recently but haven’t arrived yet (I’ll update this post if I remember!):

1. OUIDAD Moisture Lock Leave-in Conditioner
2. Marc Anthony Grow Long Biotin Leave In Conditioner Spray & Detangler for Shine - I really don’t like spray-bottle applicators, I’d rather have lotion that I rub in with my hands, but I thought I'd give a shot out of desperation (recommendation from OP u/xgypsywitchx, thank you)!