Went ahead and listed every episode of Sunny in production order according to the scripts (supplemented by the WGA Directory) + documenting which scripts we're currently missing.
For the most part, these orderings should be taken with a grain of salt, but I personally believe seasons 1-4, 6 and 8 make more sense continuity-wise (there ARE actually miniature character arcs present) when watched in production order. 13 and 17 on the other hand are good examples of filming order being prioritized and not necessarily definitive (presumably Glenn's availability for the former, and Prime Time - and parts of The Golden Bachelor - having to be filmed last because of Charlie's lack of beard), but I think it's worth noting regardless.
Here's a link to the script archive.
*Missing scripts are in red.*
Season 1:
1x01 - The Gang Gets Hip/Racist
1x02 - Charlie Got Molested
1x03 - Charlie Wants an Abortion
1x04 - Charlie Has Cancer*
1x05 - Gun Control/Fever
1x06 - Underage Drinking: A National Concern
1x07 - The Gang Finds a Dead Guy
*original pilot
Season 2:
This season is absent from the WGA website; I can't be certain of the order of the two missing scripts, though it is likely the same order as the DVD (which is different than broadcast order and the usual order on streaming services).
2x01 - Charlie Gets Crippled
2x02 - The Gang Goes Jihad
2x03 - The Gang Gives Back
2x04 - Dennis and Dee Go on Welfare
2x05 - Mac Bangs Dennis' Mom
2x06 - The Gang Runs for Office
2x07 - Hundred Dollar Baby
2x08 - Charlie Goes America All Over Everybody's Ass
2x09 - The Gang Exploits a Miracle
2x10 - Dennis and Dee Get a New Dad
Season 3:
3x01 - The Gang Finds a Dumpster Baby
3x02 - Sweet Dee Dates a Retarded Person
3x03 - Mac is a Serial Killer
3x04 - Bums: Making A Mess All Over The City
3x05 - Dennis Looks Like a Registered Sex Offender
3x06 - The Gang Solves The North Korea Situation
3x07 - The Aluminum Monster vs. Fatty McGoo (sic)
3x08 - Frank Sets Sweet Dee On Fire
3x09 - The Gang Gets Held Hostage
3x10 - The Gang Gets Invincible
3x11 - The Gang Gets Whacked (Part 1)
3x12 - The Gang Gets Whacked (Part 2)
3x13 - Dennis and Dee's Mom is Dead
3x14 - The Gang Sells The Bar
3x15 - The Gang Dances Their God Damned Asses Off
Season 4:
4x01 - The Gang Gets Extreme: Home Makeover Edition
4x02 - Mac and Dennis: Manhunters
4x03 - Mac and Charlie Die (Part 1)
4x04 - Mac and Charlie Die (Part 2)*
4x05 - Dennis Reynolds: An Erotic Life
4x06 - Frank Buys a Billboard/America's Next Top Paddy's Billboard Model Contest
4x07 - Who Pooped the Bed
4x08 - The Nightman Cometh
4x09 - The Guys/Gang Solves The Gas Crisis
4x10 - The Gang Cracks the Liberty Bell
4x11 - Mac Dates the Waitress/Mac's Banging the Waitress
4x12 - Paddy's Pub: The Worst Bar in Philadelphia
4x13 - Sweet Dee Has a Heart Attack
*Part 1 and 2 were both listed as 4x03 in the script itself, but part 2 is listed as episode 4x08 on WGA (which bizarrely lines up with the scripts as well), so I've had to bump episodes 4x05 to 4x07 down one
Season 5:
5x01 - A Very Sunny Christmas (Part 1)
5x02 - A Very Sunny Christmas (Part 2)
5x03 - Mac & Dennis Break Up
5x04 - The Waitress is Getting Married
5x05 - The Gang Hits the Road
5x06 - The Gang Gives Frank an Intervention
5x07 - The Great Recession
5x08 - The Gang Exploits the Mortgage Crisis
5x09 - Mac and Charlie Write a Movie
5x10 - The Gang Reignites the Rivalry
5x11 - Paddy's Pub: Home of the Original Kitten Mittens
5x12 - The Gang Wrestles for the Troops
5x13 - D.E.N.N.I.S./The D.E.N.N.I.S. System
5x14 - The World Series Defense
Season 6:
6x01 - The Gang Buys A Boat
6x02 - Mac's Big Break
6x03 - Mac and Charlie: White Trash
6x04 - The Gang Gets Successful (How Mac Got Fat)
6x05 - Mac Fights Gay Marriage
6x06 - Dennis Gets Divorced
6x07 - Who Got Dee Pregnant
6x08 - Mac's Mom Burns Her House Down
6x09 - The Gang Gets a New Member
6x10 - Dee Reynolds: Shaping America's Youth
6x11 - Charlie Kelly: King of the Rats
6x12 - The Gang Gets Stranded in the Woods
6x13 - Dee Gives Birth
Season 7:
7x01 - Chardee MacDennis: The Game of Games
7x02 - Frank's New Whore Wife/Frank's Pretty Woman
7x03 - The Gang Gets Connected/The ANTI-Social Network
7x04 - Frank's Brother
7x05 - The High School Reunion (Part 1)
7x06 - The High School Reunion (Part 2)
7x07 - The Gang Goes to the Movies/Thunder Gun Express
7x08 - The Storm of the Century
7x09 - The Gang Gets Trapped
7x10 - Sweet Dee Gets Audited
7x11 - Frank Reynolds' Little Beauties
7x12 - The Gang Goes to the Jersey Shore
Season 8:
8x01 - The Gang Recycles Their Trash
8x02 - Pop-Pop: The Final Solution
8x03 - The Gang Goes Virtual/Charlie Rules the World
8x04 - The Gang Dines Out
8x05 - The Gang Gets Analyzed
8x06 - Charlie and Dee Find Love
8x07 - Frank's Back in Business
8x08 - Charlie's Mom Has Cancer
8x09 - Maureen Ponderosa's Wedding Massacre
8x10 - Reynolds vs. Reynolds: The Cereal Defense
Season 9:
9x01 - The Gang Broke Dee
9x02 - The Gang Squashes Their Beefs
9x03 - The Gang Desperately Tries To Win An Award
9x04 - Mac Day
9x05 - Gun Fever Too: Still Hot
9x06 - The Gang Makes Lethal Weapon 6
9x07 - The Gang Saves the Day
9x08 - Mac and Dennis Buy a Timeshare
9x09 - Flowers For Charlie
9x10 - The Gang Gets Quarantined
Season 10:
10x01 - The Gang Beats Boggs
10x02 - Psycho Pete Returns
10x03 - The Gang Spies Like U.S.
10x04 - Charlie Work
10x05 - The Gang Goes on Family Fight
10x06 - Frank Retires
10x07 - The Gang Misses the Boat
10x08 - The Gang Group Dates
10x09 - Ass Kickers United: Going Clear
10x10 - Mac Kills His Dad
Season 11:
11x01 - The Gang Hits The Slopes
11x02 - Being Frank
11x03 - Charlie Catches A Leprechaun
11x04 - Frank Falls Out The Window
11x05 - Chardee MacDennis 2: Electric Boogaloo
11x06 - Dee Made a Smut Film
11x07 - The Gang Goes to Hell: Part 1
11x08 - The Gang Goes to Hell: Part 2
11x09 - The Maureen Ponderosa Wedding Day Massacre Defense: The Trial Of The Century
11x10 - Mac & Dennis Move To The Suburbs
Season 12:
12x01 - A Cricket's Tale
12x02 - Hero or Hate Crime?
12x03 - PTSDee
12x04 - Making Dennis Reynolds A Murderer
12x05 - Old Lady House: A Situation Comedy
12x06 - Wolf Cola: A Public Relations Nightmare
12x07 - The Gang Goes to a Water Park
12x08 - The Gang Turns Black
12x09 - The Gang Tends Bar
12x10 - Dennis' Double Life
Season 13:
13x01 - Time's Up For The Gang
13x02 - The Gang Beats Boggs: Ladies Reboot
13x03 - The Gang Wins The Sooper Bol/Big Game
13x04 - Charlie's Home Alone
13x05 - The Gang Solves The Bathroom Problem
13x06 - The Gang Escapes
13x07 - The Gang Gets New Wheels
13x08 - The Gang Remembers/The Gang Does A Clip Show
13x09 - Mac Finds His Pride
13x10 - The Gang Makes Paddy's Great Again
Season 14:
14x01 - The Gang Gets Romantic
14x02 - The Gang Chokes
14x03 - Paddy's Has A Jumper
14x04 - The Gang Texts
14x05 - The Janitor Always Mops Twice
14x06 - Thunder Gun 4: Maximum Cool
14x07 - Waiting For Big Mo
14x08 - The Gang Solves Global Warming
14x09 - A Woman's Right To Chop
14x10 - Dee Day
Season 15:
15x01 - 2020: A Year In Review
15x02 - The Gang Makes Lethal Weapon 7
15x03 - The Gang Buys a Roller Rink
15x04 - The Gang Replaces Dee With a Monkey
15x05 - The Gang Goes to Ireland
15x06 - The Gang's Still in Ireland
15x07 - Dee Sinks In a Bog
15x08 - The Gang Carries a Corpse Up a Mountain
Season 16:
16x01 - The Gang Inflates
16x02 - Frank Vs. Russia
16x03 - The Gang Gets Cursed
16x04 - Frank Shoots The Gang
16x05 - The Gang Goes Bowling
16x06 - Celebrity Booze: The Ultimate Cash Grab
16x07 - Risk E. Rat's Pizza & Amusement Center
16x08 - Dennis Takes A Mental Health Day
Season 17:
17x01 - The Gang Goes to a Dog Track
17x02 - Mac and Dennis Become EMTS
17x03 - Overage Drinking: A National Concern
17x04 - Thought Leadership: A Corporate Conversation
