I suspect many members have 2 to 3 favourite ingredients they 'go to' quite often when completing a formula. Members repeatedly get good results from using their favourite ingredients and therefore continue to go back to such ingredients when needed.
I think it would be a great resource for everyone to post a few of their favourite, often used ingredients. That way, people who are stuck in their formulation process could read about what others have successfully incorporated into past products.
I will list my favourite ingredients:
Polyhexanide - antimicrobial, preservative, cooling effect, very mild on skin
Hydroxyethylcellulose - emulsifier, stability agent, very mild on skin
Phenyl Trimethicone - silicone, great for highly increasing spf rating while keeping viscosity low
Note: The ingredients you choose to list could be ones that you have used personally, ones that you know others have used often with success, or ingredients that you might have spent much time researching, even if you didnt end up using them in the end.