Somethings that most temples (medium-big) with a fair amount of history will definitely have :
1. A Theppakulam ( Tank) somewhere in the vicinity, sometimes with a mandapam in the middle. The deity will be taken there during celebrations of the temple.
2. Much to the excitement and awe of devotees (irrespective of age), most temples used to have Elephants to be worshipped.
Though this is not a must in recent times, temples try to make sure there is an elephant for important functions and celebrations relating to the Temple.