My preference is to buy from producers who have a history of producing additive free tequila. Tapatio, El Tesoro, Ocho and Cascahuin Tahona are my favorites that are available in a lot of places. Good options include:
Arette
Cascahuin
Don Fulano
El Tesoro
Fortaleza
G4
Lagrimas Del Valle
Mijenta
Ocho
Siete Leguas
Tapatio
Terralta
Wild Common
The world of mezcal is wider, and I find that to be both more intimidating and more exciting. If the bottle tells you some detailed information about the production process and the people who make it, then you're off to a good start. Look for information like:
-Name of the individual (maestro) who produced the mezcal
-How many bottles of this batch were made
-What agave species was used
-How that agave was fermented
If a bottle answers these questions, you'll probably have an excellent tasting experience. Some brands that are favorites of mine are:
La Venenosa
Real Minero
Cuentacuentos
If you want to buy an inexpensive mezcal to make cocktails, then you have a lot of good choices that include
Banhez
Bozal
Del Maguey
Fidencio
Vago
Rey Campero
Each of those brands includes a lower price point mezcal that is tasty enough to sip and inexpensive enough to mix in a cocktail.
My all time favorites are very hard to find, but here they are.
Tequila Blanco:
Cascahuin Destino (a one time production in 2025)
or Fuenteseca Cosecha (a one time production in 2018)
Tequila Extra Anejo:
Tapatio Excellencia
Mezcal:
A 300 liter batch of inaequidens distilled in 2016 by Jose Rafeal Garcia Fernandez. It was sold in the US by Maguey Melate. Jose has unfortunately passed away.
Here are my favorites that are more available:
Tequila Blanco:
Cascahuin Tahona or Tapatio Blanco
Mezcal:
Anything that is sourced by La Venenosa. I also love anything from Cuentacuentos or Real Minero.