I know of 23 poketch apps and here they are:
Digital Watch
Comes with the poketch
Calculator
Comes with the poketch
Memo Pad
Receive from the poketch president after wining the oreburgh city gym badge
Pedometer
Come with the poketch
Pokemon list
Comes with the poketch
Friendship Checker
Receive from a girl on the first floor of the pokemon center in eterna city
Dowsing Machine
Receive from Rowan's assistant on route207 after getting the bycycle
Berry Searcher
Receive from girl in the berry man's house on route 208
Day care checker
receive from the boy at the pokemon day care house in solaceon
Pokemon History
receive from a boy in Solaceon
Counter
Receive from the receptionist on the secound floor of the Veilstone department store
Analog watch
Receive from a private house in Celestic town
Marking map
Receive from the Poketch president after winning the hearthome gym badge
Link searcher
Receive from the poketech president after winning the Pastoria gym badge
Coin toss
Recive from a boy in the cottage along route 213 after winning the Snowpoint Gym badge
Move tester
Recive from the poketch president after winning the Snowpoint gym badge
Calendar
Receive after showing a pokemon with a serious nature to a boy in a private house in sunyshore city
Dot Artist
Showing a Pokemon with a Naive Nature to the boy
Roulette
Showing a pokemon with a Quirky Nature to the boy
Trainer Counter
Receive from Professor oak at the pal park along route 221
Kitchen timer
Receive after showin a girl on the first floor of the pal park a snorlax
Color Changer
Show the girl in the pal park a kecleon
Match up checker
Catch more than five pokemon in one game at the marh in pastoria city and talk to the girl
I hope this helps
Digital Watch
Comes with the poketch
Calculator
Comes with the poketch
Memo Pad
Receive from the poketch president after wining the oreburgh city gym badge
Pedometer
Come with the poketch
Pokemon list
Comes with the poketch
Friendship Checker
Receive from a girl on the first floor of the pokemon center in eterna city
Dowsing Machine
Receive from Rowan's assistant on route207 after getting the bycycle
Berry Searcher
Receive from girl in the berry man's house on route 208
Day care checker
receive from the boy at the pokemon day care house in solaceon
Pokemon History
receive from a boy in Solaceon
Counter
Receive from the receptionist on the secound floor of the Veilstone department store
Analog watch
Receive from a private house in Celestic town
Marking map
Receive from the Poketch president after winning the hearthome gym badge
Link searcher
Receive from the poketech president after winning the Pastoria gym badge
Coin toss
Recive from a boy in the cottage along route 213 after winning the Snowpoint Gym badge
Move tester
Recive from the poketch president after winning the Snowpoint gym badge
Calendar
Receive after showing a pokemon with a serious nature to a boy in a private house in sunyshore city
Dot Artist
Showing a Pokemon with a Naive Nature to the boy
Roulette
Showing a pokemon with a Quirky Nature to the boy
Trainer Counter
Receive from Professor oak at the pal park along route 221
Kitchen timer
Receive after showin a girl on the first floor of the pal park a snorlax
Color Changer
Show the girl in the pal park a kecleon
Match up checker
Catch more than five pokemon in one game at the marh in pastoria city and talk to the girl
I hope this helps