On a simple ring with one key, meaning all the locks are alike, with the key on a large wall nail.
"The one key ring to rule them all."
Coin doors are keyed alike only.
Back boxes and ticket dispensers are independent keys and locks, if applicable.
"Simple and practical is better."
This works best for home use, not operated route games that require added security against key copying theft.
Spare keys for the same lock series are in my toolbox (on a giant ring), car ring, and couple other critical locations.
I buy locks in bulk, in lots of 100+.
I have bought at least two lots? as a collector (maybe more), as tumblers can still be matched sometimes for reuse, as I ended up with identical lots if a person asks upfront to parts suppliers.
Any games traded or sold, the locks are simply swapped with old original locks in my parts bins.
It works very well.
Spending excessive money on lockboxes, keyrings, magnets, and and colorful newly designed non factory fobs is wasteful and actually costs more money in the long run than owning keyed alike locks. Pinball machines are are not motorcycles or cars where the locks and ignition keys are valuable in themselves. I put factory keychain fobs go back into the cash boxes.
If a collector has only a few games with non-identical locks, attach with a wood screw the extra key on the underside of the cabinet near the coin door, in case the specific key is lost. This will save yourself switching out another lock via pick or drilling, especially if a barrel torx style. You will thank me for this advice later.