My staple products are:
1. Coconut oil (pre-poo, detangle)
2. Castile soap (wash)
3. AO Honeysuckle Rose Conditioner
4. Alba Botanicals Leave-In (used as leave-in or a tiny bit diluted to spritz my hair in between wash days)
5. Jojoba Oil (to seal in moisture after spritzing)
This is my cold weather routine. During warm days of spring and summer, I use the coconut oil to seal.
Most of my other products (other conditioners, herbs and butters) I have because I was trying to figure out what worked for me. As I used them up or give them away, I won't rebuy.
The only addition I'll make to my list (#6) is a light conditioner suitable for co-washing. For now, that's Trader Joe's Tea Tree Tingle conditioner. I don't do it often, but it's great when my hair is extra dry, plus it has a little protein.