Frequent collaborators:

Diamond level (21-30 papers): 

Béla Bollobás (29) 

Platinum level (15-20 papers): 

Rob Morris (19), 

Felix Christian Clemen (15), Bernard Lidicky (15), 

Wojtek Samotij (15) 

Gold level (10-14 papers):

Alexandr Kostochka (12),  Hong Liu (12), Andrew Treglown (12),

Adam Zsolt Wagner (11),
Andras Pluhár (10), Maryam Sharifzadeh (10), 

Silver level (5-9 papers): 

Gelasio Salazar (9), 

Lina Li (8),  

Noga Alon (7), Ping Hu (7), Haoran Luo (7), Misha Lavrov (7), 

Xujun Liu (6), Dhruv Mubayi (6), John Lenz (6), 

Igor Araujo (5), Béla Csaba (5), Ryan Martin (5), 

Bronze level (2-4 papers):  

Jane Butterfield (4),  Ce Chen (4), Ramon Garcia (4), Emily Heath (4), Robert Krueger (4), Will Linz (4), Leticia Mattos (4), Theo Molla (4), Bhargav Narayanan (4), Miklos Simonovits (4), David Weinreich (4),   Cory Palmer (4),

Michelle Delcourt (3), Peter Keevash (3),  Jesus Leanos (2), Sarka Petrickova (3), Florian Pfender (3), Jozef Skokan (3), Benny Sudakov (3), Jan Volec (3),

Maria Axenovich (2), Tom Bohman (2), János A. Csirik (2) , Shagnik Das (2), Adrian Dumitrescu (2), Sean English (2), Choongbum Lee (2), Richard Mycroft (2), Balázs Patkós (2), Gabor Pete (2), Boris Pittel (2), Noah Prince (2), Cliff Smyth (2), Tuan Tran (2), Mark Walters (2).

Frequent pairs of collaborators:

Gold level (10-14 papers):

Béla Bollobás -- Robert Morris (12) 

Silver level (5-9 papers): 

Hong Liu -- Maryam Sharifzadeh    (9)

Felix  Clemen -- Bernard Lidicky (6) 

Alexandr Kostochka -- Xujun Liu (6)

Robert Morris -- Wojciech Samotij (6) 

Bronze level (2-4 papers):  

Béla Bollobás -- David Weinreich     (4)

Noga Alon  -- Robert Morris (3)

Noga Alon  -- Wojciech Samotij (3)

Béla Bollobás  -- Miklós Simonovits (3)

Felix Clemen -- Michael Lavrov (3)

Béla Csaba   -- András Pluhár         (3)

Peter Keevash -- Benny Sudakov (3)

Jesus Leanos -- Gelasio Salazar (3)

Bernard Lidicky -- Florian Pfender (3)

Bernard Lidicky -- Jan Volec (3)

Andrew Treglown -- Adam Wagner  (3)

Noga Alon -- Béla Bollobás (2)

Béla Csaba -- Wojciech Samotij     (2)

Felix Clemen -- Adrian Dumitrescu (2)

Ramon Garcia -- Lina Li (2)

Ping Hu -- John Lenz (2)

Ryan Martin -- András Pluhár (2)

Frequent triplets of collaborators:

Bronze level (2-4 papers):  

Alexandr Kostochka -- Michael Lavrov -- Xujun Liu (3)

Noga Alon  -- Robert Morris -- Wojciech Samotij (2)

Jane Butterfield -- Ping Hu -- John Lenz (2)

Felix Clemen -- Emily Heath -- Michael Lavrov (2)

Shagnik Das -- Hong Liu -- Maryam Sharifzadeh (2)

Ping Hu -- Bernard Lidicky -- Jan Volec (2)

Hong Liu -- Maryam Sharifzadeh -- Andrew Treglown   (2)

Note: pairs are not listed if their multiplicity is the same as a triplet containing it.