Just had heavy rain ride

it there was heaps of road spray, there's a good chance there's water in your frame!! It's amazing how it gets in there. Is there a drain hole under your bottom bracket? If not, undo the screw holding the gear cable guide under there, and see if any water drips out. If your bottom bracket threads weren't greased when put in, there's a slight chance that corrosion and subsequent seizing could occur.

Also, take off your tyres and see if the rims are full of water.

With the chain, just give it a whipe and oil.

If you wanna get really keen, just about every threaded part should be greased, especially the pedals, bottom bracket, cranks and chainring bolts -- these parts commonly seize up. The seatpost should also be greased, but not if it's carbon. Slightly less important are the rear derailleur hanger, front derailleur clamp, seat post bolt, seat clamp, brake bolts, all stem bolts, etc.

Have I made you paranoid? 🙂

You can go all out as 531 has proposed, but it does seem a bit overboard.

In my case I would wipe down the bike and do a chain cleaning/greasing session.

Usually what I do in that situation is immediately dry with compressed air. You can really get the water out of tight places. If I have more time I'll wash with a mild detergent and do the air thing and wipe every thing with a soft cloth. Don't wipe a dirty bike (scratches the frame). And, as 531Aussie suggests, you may want to check for water in the rims. Follow all this with a lube job and your good to go!!!