I've recently gotten very into Critical Role, which is a dungeons and dragons campaign played by a bunch of super talented voice actors on a Twitch stream every week. I'm only on episode 5 and there are like 90 something episodes (?) so I have a looot to catch up on, BUT I just found my first sneeze!
Episode 5 "The Trick About Falling"; around 2:10:15 Liam starts making a really nice pre-sneeze face 
Afterwards Laura and a few of the others bless him, which is cute.
My plan is to keep adding sneezes to this thread as I find them, but those of you that are further ahead of me, please jump in if you've found some!
Edit: Thread Masterlist
Chapter One
Episode 3 - Travis (2 stifles), Marisha - 40:20; 42:32
Episode 5 - Liam - 2:10:15
Episode 6 - Travis - general cold/sickness
Episode 9 - Sam - 2:34:38
Episode 10 - Liam - 2:01:00
Chapter Three
Episode 26 - Liam, Matt - 1:04:24; 4:03:00
Episode 28 - Marisha - 00:49:00
Episode 30 [Halloween ep] - Liam (faked?) - 1:59:48
Episode 31 - Travis, Liam - 00:09:51; 01:54:19
Episode 32 - Ashley (via Skype) - 03:01:00
Episode 33 part 2 - Travis? (off-screen); Liam's voice grows progressively hoarser throughout - 1:08:20
Episode 34 - Taliesin - 3:12:50, 3:13:35, 4:14:23
Episode 35 part 1 - Travis (off-screen) - 00:06:50
Episode 38 - Matt - 4:21:24
Chapter Four
Episode 51 - Matt (double, off-screen) - 1:11:45
Episode 52 - Marisha, Ashley - 00:56:12; 3:09:40
Episode 53 - Marisha - 00:57:35
Chapter Five
Episode 57 - Liam - 2:31:30
Episode 63 - Laura (almost + discussion); Laura is clearly sick throughout - 00:10:55
Episode 65 - Liam, Sam - 01:11:18; 2:05:45
Episode 67 - Unknown (Laura?) offscreen - 00:06:26 right after intro
Chapter Six
Episode 73 - Marisha - 1:41:25
Episode 75 - Matt - 2:26:45
Episode 77 - Ashley (or a cough?) - 2:47:15; has lost her voice and discusses it at 1:15:26
Episode 78 - Marisha - 1:05:18
Episode 81 - Sam (double) - 1:34:32
Episode 82 - Taliesin is stuffy & mentions having a cold at the beginning of the episode
Chapter Seven
Episode 85 - Marisha, Travis (stifled fit of three + fourth) - 1:41:42; 3:16:20
Episode 89 - Marisha - 3:09:44
Episode 93 - Matt (double + one more) - 2:58:37, 2:59:08
Episode 94 - Ashley - 1:33:05
Episode 96 - Ashley (x2), Laura - 00:43:45, 00:44:05; 1:52:06
Chapter Eight
Episode 100 - Marisha - 1:09:10
Episode 106 - Marisha - 3:31:12
Episode 107 - Taliesin (double) - 3:41:22
Extras
Liam's Quest - Laura - 00:35:51
Just Dance (Matt dances to Applause) - Travis - 3:49, 3:56
-> I believe this is just post-ep 6 where he's leaving the whole episode to sneeze/blow his nose