I was bored so I made this list
Season 1:
One: 1
Another One: 1, 2
Two: 1, 2
Three: 1, 2, 3
One, Two, Three: 1, 2, 3
Four: 1, 2, 3, 4
Five: 1, 2, 3, 4, 5
Three Little Pigs: 1, 2, 3, 4, 5
Off We Go: 1, 2, 3, 4, 5
How To Count: 1, 2, 3, 4, 5, The Flapjack Snaffler
Stampolines: 1, 2, 3, 4, 5
The Whole of Me: 1, 2, 3, 4, 5
The Terrible Twos: 1, 2 (Dublo, The Terrible Twos), 3, 4, 5
Holes: 1, 2, 3, 4, 5
Hide and Seek: 1, 2, 3, 4, 5
Season 2:
Six: 1, 2, 3, 4, 5, 6
Seven: 1, 2, 3, 4, 5, 6, 7
Eight: 1, 2, 3, 4, 5, 6, 7, 8
Nine: 1, 2, 3, 4, 8, 9
Ten: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Just Add One: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Blast Off: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Aliens
Counting Sheep: 1, 2, 3, 4, 5, 6, sheep
Double Trouble: 1, 2, 4, 8
The Three Threes: 1, 2, 3 (Tryplo, The Three Threes), 4, 5, 6, 7, 8, 9, 10
Odds and Evens: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Fluffies: 1, 2, 3, 4, 5, 6, 7, 8, Fluffies
The Two Tree: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Numberblock Castle: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Ten Green Bottles: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Season 3:
Once Upon A Time: 1, 2, 3, 4, 5, Squarey
Blockzilla: 1, 2, 3, 4, 5, Blockzilla
The Numberblocks Express: 1, 2, 3, 4, 5
Fruit Salad: 1, 2, 3, 4, 5
Zero: 0, 1, 2, 3, Flapjack Snaffler
Now We Are Six To Ten: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Numberblobs: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Numberblobs
Building Blocks: 6, 7, 8, 9, 10, Aliens
Peekaboo: 1, 2 (Dublo, The Terrible Twos), 3, 4, 5, 6, 7, 8, 9, 10
Hiccups: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Squarey
What's the Difference: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Numberblobs
Numberblock Rally: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Five and Friends: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Octoblock to the Rescue: 1, 2 (Dublo, The Terrible Twos), 3, 4, 5, 6, 7, 8 (Octoblock, Octonaughty)
Ten Again: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Rainbows
Season 4:
Flatland: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Squarey, Flatlanders
Pattern Palace: 1, 2, 3, 4, 5, 6
The Legend of Big Tum: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Big Tum
Mirror, Mirror: 1, 2 (Dublo, The Terrible Twos), 3 (Tryplo, The Three Threes), 4, 5, 6, 7, 8, 9, 10
The Wrong Number: 1, 2, 3, 4, 6, 9, 11
Eleven: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, Numberblobs
Twelve: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
The Way of the Rectangle: 2, 3, 4, 6, 8, 12
Ride the Rays: 1, 2, 3, 4, 5, 6, 10, 12
Block Star: 1, 2, 3, 4, 5, 6, 7, 8, 9, 12
Thirteen: 1, 3, 10, 11, 12, 13
Fourteen: 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14
Fifteen: 1, 2, 3, 4, 5, 8, 9, 10, 15, cat
Tween Scenes: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, Numberblobs
Step Squads: 1, 2, 3, 4, 5, 6, 10, 15
Fifteen's Minute of Fame: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, Numberblobs
On Your Head: 0, 1, 2, 3, 4, 5, 7, 10, 11, 12, 13, 14, 15
Ten's Place: 1, 2, 3, 4, 5, 10, 11, 12, 13, 14, 15c
Balancing Bridge: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, Numberblobs
Sixteen: 1, 2, 4 (Esquardo, The Four Fours), 6, 8, 9, 10, 12, 16
Square Club: 1, 2 (The Terrible Twos), 3 (Tryplo, The Three Threes), 4 (Esquardo, The Four Fours), 9, 16
Seventeen: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17
Eighteen: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18
Loop the Loop: 2, 3, 6, 7, 9, 10, 12, 14, 15, 16, 18
Nineteen: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19
Twenty: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Tall Stories: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
Flights of Fancy: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
I Can Count To Twenty: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 (compound), Numberblobs
Heist: 1, 4, 7, 8, 9, 10, 16, 17, 18, 19, 20
Sign Of The Times: 2, 3, 4, 6, 8, 9, 10, 12, 15, 16, 18
Fun Times Fair: 2, 3, 4, 6, 12, Numberblobs
The Lair Of Shares: 1, 2, 3, 4, 5, 6, 12, 15, 20
Terrible Twosday: 1, 2 (Dublo, Terrible Twos), 4, 5, 6, 8, 10, 12, 14, 17, 18
Divide and Drive: 3, 4, 6, 9, 12, 16, 18
Twenty-One and On: 1, 2, 3, 4, 5, 6, 7, 10, 11, 20, 21 (compound and figured-out), 22 (compound and figured-out), 23 (compound)
We're Going on a Square Hunt: 1, 2 (Terrible Twos), 4, 9, 16, 20, 21 (figured-out and compound), 22 (compound), 23 (compound), 24 (compound), 25 (compound and figured-out)
Thirty's Big Top: 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50
Land Of The Giants: 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50
Fifty: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 20, 25, 30, 35 (compound), 40, 45 (compound), 50
Sixty's High Score: 1, 6, 7, 8, 9, 10, 60, 70, 80, 90
The Big One: All numbers from 0-100 (numbers bigger than 20 are compound)
One Hundred: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 16, 20, 25, 50, 60, 70, 80, 90, 99 (compound), 100
The Episode with an unknown name: 1, 10, 100, 101-103 (compound), 110 (compound), 120 (compound), 130 (compound), 200, 300, 900, 990 (compound), 999 (compound), 1000, 10000, 100000, 1000000
More To Explore: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 25, 30, 36 (drawing), 40, 42 (drawing), 49 (compound and drawing), 50, 60, 64 (compound and drawing), 70, 80, 90, 95-99 (compound), 100, 123-125 (compound), 97104 (coumpound), Blockzilla, Big Tum