FTM here as well, I would say have a wide variety of prices...some people will only be looking to spend $20-$25 while others may spend more or even go in together on a larger item.
I did the same thing as you, only registered for the larger items because I wasn't expecting to have a shower and I wanted to use the completion coupon on them, so when MIL insisted on throwing us a shower, I had to go back and add lots of things.
Maybe some ideas - books, soap, lotion, shopping cart cover, tub, health items (thermometer, nail clippers, etc), bottles, sun shade, towels, wash cloths, sheets, changing pad and cover...just look up lists of registry items online and add what applies to you.
And people won't buy exclusively off your registry either, we received lots of extra things that we hadn't registered for. We didn't register for clothes and it seemed Ike everyone brought an outfit...or 10 :) thankfully they covered the whole first year, and weren't all newborn.