Standard Interfaces (Subset):

Database.Batchable :

global (Database.QueryLocator | Iterable<sObject>)
 start(Database.BatchableContext bc) {}
global void execute(Database.BatchableContext BC, list<P>){}
global void finish(Database.BatchableContext BC){}

Schedulable:

global void execute(ScheduleableContext SC) {}

Messaging.InboundEmailHandler:

global Messaging.InboundEmailResult handleInboundEmail(Messaging.
inboundEmail email, Messaging.InboundEnvelope env){}

Comparable:
global Integer compareTo(Object compareTo) {}