Salvador Vidal. Arguably the most well-known male voice in Spain, even though his name isn't nearly as publicly famous as Constantino Romero or Ramón Langa. He has voiced most of Holywood mature stars of the last 40 years: George Clooney, Harrison Ford, and Michael Douglas are just a few examples. Not to mention that he is insanely prolific in advertising, which gives a lot of people the impression that he is practically everywhere.
Constantino Romero. Probably the most famous voice actor in Spain, since, unlike most voice actors in the country, most people know his face due to his work as a successful TV host. Also, some of the most famous pop culture classics has been voiced by him. For starters, he's Clint Eastwood's regular voice actor. Then he was the Terminator in first three movies, Mufasa, Judge Claude Frollo... and Darth Vader.
Nuria Trifol. She is one of the most prolific voice actresses for children and female teenagers in Spain, although she's perfectly capable of adult women. Extra points for being also in practically every single Spanish anime dubbing recorded in Barcelona, and doing important roles most of the time. In fact, she has appeared even more in Catalonian dubs. She's also Keira Knightley's usual voice actress in Spain.
Graciela Molina. She rivals Nuria Trifol in the most prolific voice actress for children and female teenagers, although she's a little bit more focused in young adult women and way more in live action. Fun fact: both actresses act together often in female friends and kid siblings roles, and both of them dub Natalie Portman regularly.note The Natalie Portman part has an anecdote: Molina voiced Padme in Episode I, while Trifol voiced her decoy (performed by Keira Knightley). However, this led to a confusion in Lucasfilm, making them to cast Trifol for Episodes II and III.
Luis Bajo. The same as Salvador Vidal, but in TV Shows rather than film. He's also becoming the Spaniard equivalent of Nolan North in video games (although he has a wider range of voices than North). During the last three years or so, it seems like he's everywhere in digital media. He also voiced the Joker in Batman, and his performance is impressive in its own right, even after you compare it to Mark Hamill's.
Eduardo Garza is either casted for characters who are either fat, dorky, arrogant, fun-personified, calm, tempered, weird (Xander, anyone?), or someone who ends up dying (with Krillin and Kohaku the well-known examples, albeit they got better).
According to Garza himself, he always wanted to voice handsome boys, but when he got the voice role of Francis, which at first glance is described as that, he then realizes that the character is an "imbecile" in terms of personality, albeit he ended up voicing the character nonethless.
The late Enrique Mederos was the definition of voice versatility. During his time in voice acting, he can voice little boys, young adults and even elderly men; and can modulate every tone. Well known examples are the roles he had in Dragon Ball Z such as Pikkon and Old Kai, as well as Fujitaka Kinomoto (Sakura's dad) and Ryota Miyagi in Slam Dunk.
The closest thing Mederos has for modern day successors are Luis Leonardo Suarez and Héctor Ireta de Alba.
Colombian-born Juan Carlos Tinoco is the definition of voice manliness, with characters he voiced such as Jiren, Brian Griffin (since Season 4), Luke Hobbs and Thanos. It does help his voice is so relaxing that you can feel the masculinity emmanating from his tone.
The characters that are voiced by Luis Daniel Ramírez are either handsome, heroic, fat, nice, dorky, dumb or even anthromorphic. When it comes to either voicing the same character or starring roles together, he's the Blue Oni to Eduardo Garza's Red Oni, making him a Foil of sorts.