Soulful games are generally created by a small development team (in terms of design, programming, and graphics), as in this list the Codex generated a few years ago:
1 Person
Akalabeth (1980), Ultima (1981), Ultima II (1982), Ultima III: Exodus (1983): Richard Garriott
Missile Command (1980): Dave Theurer
River Raid (1982): Carol Shaw
Alley Cat (1983): Bill Williams
The Lords of Midnight (1984): Mike Singleton
Tetris (1985): Alexei Pazhitnov
Doomdark's Revenge (1985): Mike Singleton
The Faery Tale Adventure (1986): David Joiner (including the music!)
SimCity (1989): Will Wright
Prince of Persia (1989): Jordan Mechner
Captive (1990): Antony Crowther
Another World (1991): Eric Chahi
Nahlakh (1994): Tom Proudfoot
ADOM (1994): Thomas Biskup
Papers, Please (2013): Lucas Pope
Paper Sorcerer (2013): Jesse Gallagher
NEO Scavenger (2014): Daniel Fedor
Grimoire: Heralds of the Winged Exemplar (2017): Cleveland Blakemore
Return of the Obra Dinn (2018): Lucas Pope
2 People
Wizardry: Proving Grounds of the Mad Overlord (1981): Andy Greenberg & Robert Woodhead
Galaga (1981): Shigeru Yokoyama & Toru Ogawa
Elite (1984): Ian Bell & David Braben
Boulder Dash (1984): Peter Liepa & Christopher Gray
Emerald Mine (1987): Klaus Heinz & Volker Wertich
Space Quest II (1987): Mark Crowe & Scott Murphy
Dark Heart of Uukrul (1989): Ian Boswell & Martin Buis
Exile (1995): Jeff Vogel & Andrew Hunter
Natuk (1999): Tom Proudfoot & Dave Gerry
Dwarf Fortress (2006): Zach Adams & Tarn Adams
Super Meat Boy (2010): Edmund McMillen & Tommy Refenes
Salt & Sanctuary (2016): James Silva & Michelle Juett Silva
3 People
Rogue (1980): Michael Toy, Glenn Wichman, & Ken Arnold
Pac-Man (1980): Toru Iwatani, Shigeichi Ishimura, & Shigeo Funaki
Archon (1983): Anne Westfall, Jon Freeman, & Paul Reiche III
Might & Magic (1986): Jon Van Caneghem, Michaela Van Caneghem, & Mary Ellen Bloom
Sid Meier's Pirates! (1987): Sid Meier, Michael Haire & Arnold Hendrick
World of Goo (2008): Kyle Gabler, Ron Carmel, & Allan Blomquist
Knights of the Chalice (2009): Pierre Begue, Kelly Brake, & Marcel Králik
Hollow Knight (2017): Ari Gibson, William Pellen, & David Kazi
4 People
Battlezone (1980): Ed Rotberg, Jed Margolin, Howie Delman, & Roger Hector
Seven Cities of Gold (1984): Dan Bunten, Jim Rushing, Bill Bunten, & Alan Watson
Space Quest (1986): Mark Crowe, Scott Murphy, Sol Ackerman, & Ken Williams
Leisure Suit Larry (1987): Al Lowe, Mark Crowe, Ken Williams, & Chuck Benton
Dungeon Master (1987): Doug Bell, Mike Newton, Dennis Walker, & Andy Jaros
X-Com (1994): Julian Gollop, Nick Gollop, John Reitze, & Martin Smillie
Geneforge (2002): Jeff Vogel, Andrew Hunter, Brian Snoddy & Linda Strout
Braid (2009): Jonathan Blow, David Hellman, Sean Barrett, & Edmund McMillen
Legend of Grimrock (2012): Petri Häkkinen, Antti Tiihonen, Juho Salila, & Olli Pelz
Ghost of a Tail (2016): Lionel Gallat, Cyrille Paulhiac, Paul Gardner, & Jerome Jacinto