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
CAMPAIGN ONE: THE TALES OF VOX MACHINA
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 24 - Marisha - 1:20:45
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
Episode 47 - Laura (stifle) - 2:56:34
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, Marisha - 2:26:45, 3:42:20
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 (double), Laura - 00:43:45, 00:44:05; 1:52:06
Chapter Eight
Episode 100 - Marisha - 1:09:10
Episode 104 - Ashley - 00:26:16
Episode 105 - Marisha (almost); Laura (almost) - 1:20:19; 3:37:45
Episode 106 - Marisha - 3:31:12
Episode 107 - Taliesin (double) - 3:41:22
Episode 109 - Laura - 3:37:45
CAMPAIGN TWO: THE MIGHTY NEIN
Episode 1 - Travis (discussion/sniffles re: Fjord's cat allergy) - starts 1:01:06
Episode 3 - Taliesin - 3:04:08
Episode 5 - Sam - 2:37:38
Episode 4 - Travis (stifles) - 3:31:33, 3:31:47
Episode 6 - Laura "blesses" Taliesin (who fakes) - 1:30:20
Episode 8 - Travis (nose-scrunching from cat); Marisha (and ensuing discussion about her injuring her rib doing so); Liam (fake) - 42:42; 1:27:17; 2:05:18
Episode 11 - Liam; Marisha - 46:12; 3:58:47
Episode 12 - Travis (stifle) - 37:11
Episode 14 - Taliesin (off-screen) - 8:15
Episode 16 - Liam - 52:50
Episode 19 - Ashley (fake) - 1:10:20
Episode 20 - Sam - 3:20:30
Episode 32 - Sam (double) - 1:41:50
Episode 33 - Marisha - 56:32, 3:49:12
Episode 38 - Marisha - 13:07
Episode 40 - Sam; Liam - 26:00; 1:56:22, 2:43:52
Episode 42 - Marisha - 1:09:15
Episode 43 - Matt (triple) - 3:11:41
Episode 46 - Liam - 3:34:09
Extras
Liam's Quest - Laura - 00:35:51
Just Dance - Travis - 3:49, 3:56
C2E2 Panel 2018 - Liam (fake) - 25:55
Epic Level Battle Royal - Marisha - 3:34:07
Talks Machina Episode 80 - Sam - 22:27ish on Alpha
Talks Machina Episode 82 - Matt (fake)
Honey Heist 3: Tova's Honeys - guest Krystina Arielle - 1:36:25