selection of ic board

I have 20 sensors. The board has to receive signals from all the sensors and send the signals to 3 other components.. The board should be highly reliable. I have to program the board so as to send the signal only above certain limit. Please suggest me a good IC board

Since this is an Arduino forum, start with this, get 23 connectors, and then progress as you get to be a little more forthcoming about what you want to do, what the sensors are and, perhaps, what you want to sense.

You never know what might be helpful, but few people are going to bother trying to crack your secrets.

The board should be highly reliable

This forum is for Arduino family of boards, which are primarily intended for hobbyist use.

If you require a “highly reliable” board, you should contact the major component suppliers for advice.
AFIK the Atmel processors on these boards are Not rated for many applications like medical etc, check the specs on the Atmega series of ICs on the Atmel websit

If however you are OK with a board intended for hobbyists, you have not provided enough information to give you a useful response.

e.g.

I have 20 sensors

This isn’t enough information, are these sensors analogue or digital, what sample rates arequired etc.

send the signals to 3 other components

No use either. These components could be anything, either analogue or digital