19.
Buckle up, Spoiler alerts, some dozens of years old:
Thunderball, 1965:
All of them: 001, 002, 003, 004, 005, 006, 008, 009 (8+007).
All 00 are called to Whitehall as SPECTRE holds the world hostage with 2 nukes stolen from NATO.
By the way, the number of agents is expended from 9 in later Bond books and films.
Octopussy, 1983:
009 was on to to plot of trading stolen priceless Russian artifacts and manages to deliver a Fabrege Egg to the residence of the British Ambassador in West Germany, but dies from his wound as he does. The clown costume shows you he was pretty far along in the case, as the movie progresses.
007 completes 009’s investigation and assignment and also avenges 009.
RIP 009.
A View to a Kill, 1985:
003 (Deceased).
003 manages to get the chip the Russians got from Zorin, but doesn’t manage to extract, 007 completes the assignment.
RIP 003.
The Living Daylights, 1987
002 and 004 participate in a drill in Gibraltar alongside 007. Fortunately for 002 he is mock “killed” by SAS, granted, failing the drill. Alas, 004 is less lucky, getting killed by an assasain, who 007 later takes out, beginning the plot of the film by chasing what is eventually discovered to be a false flag operation.
RIP 004.
GoldenEye, 1997
006 (Alec Trevelyan) and 007, raid the Arkangel Chemical Weapons Facility in the USSR, for England. 006 is captured and “Killed”, but as it turns out, he is actually a traitor and the man behind the movie’s plot, to steal and use the Russian weapon “GoldenEye”. Bond foils the plan and takes Trevelyan out. Not for England, for himself.
Burn in hell 006.
The World is Not Enough, 1999
5 unspecified 00s in addition to 007 are called in to Glan Derrock estate in Scotland, in order to investigate attack on the SIS building in London, Bernard King’s murder and the connection these have to the terrorist Renard, eho 009 almost killed before the events. 007 is there as a courtesy, he is not briefed, considered out of commission. But, of course, that doesn’t stop him.
If you really want to double down on “shown” you can mention 0012, in the same movie.
His photo is shown when 007 investigates his death and retrieves the money paid to Elektra King’s kidnappers. 007 evetually avenges 0012 (It was Renard who killed him.
Since you don’t see “him” him, I won’t count him but RIP 0012.
No Time to Die, 2021
The new 007, M. Nomi, is a signifcant part of the plot, highly capable but innitally hostile and arrogant towards Bond, and evetually helpful and respectful, assisting in the succesful outcome and protecting Bond’s loved ones.
Additional 00 agents are mentioned but not shown in several films and several MI6 agents are shown but are not 00s.
So yes, 19, quite a few.