The best wood rasps have somewhat irregularly cut teeth.
The older nicholson 49 and 50 “Patternmakers” rasps were quality, but that was before the rasp production got sent yo South America(Brazil I think) and the quality went to ****. Nicholson had a special Rasp Cutting machine that cut slightly irregular teeth, and either they fisn’t send it to South America, or the locals don’t know how to properly set the equipment up, or maybe don’t care to?
Most rasps with perfectly aligned teeth sort of ****, at least for wood if the wood is even halfway hard.
The best current rasps are either cut by hand, nowadays, or the rasps are machine made with a completely different tooth design than was used on older machine made rasps.
The best hand cut Rasps are made in France by either Liogier or Auriou.
With Liogier you can order direct from France, or purchase from several or more dealers in the USA.
Auriou rasps are sold thru specialty woodworking dealers in the USA like Lee Valley or Highland Hardware.
I’m not sure if either brand is really better than the other.
The rasps aren’t cheap.
Another source for hand cut rasps is ToolsForWorkingWood in NYC. They sell a house brand of rasps called “Gramercy”. The rasps are hand cut, made from surgical grade stainless steel in Pakistan, I presume by one of the makers of many makers surgical tools located in Pakistan, who presumably already made rasps.
There’s also Narex from the Czech Republic, whose rasps look like a step up from cheap machine made rasps, but not the quality of Gramercy, Auriou, or Liogier.
The price is a bit better.
for Machine made rasps, Vallorbe of Switzerland, makes a high quality machine cut rasp that is considered almost as good as a hand cut rasp, but the rasps are somewhat close in price to a hand cut rasp, and I think they have multiple patterns, so you have to figure out which ones are the “patternmaker” version(these are the good ones).
Corradi, an Italian file maker, also made a similar high quality rasp, but I’m not sure if there are any US sources other than for tiny rasps.