One of my strongest opinions about art supplies and materials I use is that less can be WAY more. Having too many supplies and brushes and materials to choose from is one more pause and distraction for me when it comes to being able to sit down and start creating. (This is just my opinion, and may not be the same for you). I think the perfect selection for me is #2, #6 and #8 or 10 Round. I find even when I have other options these are the ones I reach for 99% of the time.
Even looking at the picture above of my brush collection I feel a little overwhelmed like it's too many to choose from (full disclosure I have more that I don't use and should re-home).
So what do I recommend to someone who wants to start out?
1. Think about the size of the work you are going to be creating: do you just want to work in your sketchbook? (like in my new online course?!?) or do you want to do larger (8x10" or larger) pieces.
2. Do you like broad sweeping strokes or details? Do you want the flexibility to be able to do both?
3. Natural hair brushes like squirrel and sable hold more water than synthetic versions, though those have come a long way in quality recently. Synthetic is more affordable but made from plastic, natural is more expensive and made from animal hair. I love checking "used" platforms like Mercari for supplies whenever possible ( one nice brush you love is better than having too many).
4. How much control do you like to have? And as alluded to above- more control means more snap in the bristles - kolinsky sable synthetics will have the most control, squirrel and squirrel synthetics will be more mop-like and soft.
My personal favorite NICE brush that I think covers it all is The Signature Series 50/50 size 6 Round from Joe Miller of Cheap Joes it runs around $19 - $30 - carries a lot of water yet still comes to a beautiful point - its the 4th one from the left.
Princeton Neptune brushes are a nice synthetic squirrel option in the round, size 6 or 8 is under $10 on Cheap Joe's
The red handled Princeton Heritage brushes pictured above are a little stiff for my taste, but if you are just starting out they may be perfect for you, giving you more control while you work.
There are some nice affordable brush sets and travel sets for just $20, found on Amazon.
My opinions are likely to change, but this is where they stand today.