Safe to mass find and replace:

• yze –> yse
• iza –> isa
• color –> colour
• honor –> honour
• maneuver –> manoeuvre
• armor –> armour
• favor –> favour
• travele –> travelle
• laborer –> labourer
• laborers –> labourers
• recognized –> recognised
• meager –> meagre
• caliber –> calibre

Check manually:

• fulfill –> fulfil
• labor –> labour (watch out for inadvertently changing “elaborate” or “collaborate”)
• ize –> ise (watch out for inadvertently changing “seize”)
• izing –> ising (watch out for inadvertently changing “seizing”)
• fense –> fence
• eled –> elled
• vior –> viour
• center –> centre