I'm building a general purpose LED board using the PWM pins on an ATTiny85 chip. The chip will be mounted on a dip socket, so it can be removed and reprogrammed as desired. When on the LED board, the reset pin will not be used. I want to make sure the chip doesn't randomly reset, as I assume it could since the reset pin would be floating. I've read a few articles/posts about disabling or reassigning the reset pin as I/O, but that's not what I want to do.
Is the best way to just pull up with a 10k resistor?
I always use a 10K pullup on the reset pin. There may be an internal pullup, but it is weak and susceptible to noise. With a 10K pullup, I have never had any trouble with unanticipated resets.
What core are you using? If I may, I would like to recommend the ATTinyCore core. It is the best core that I have found for those parts. It is available via the IDE boards manager.
I just double checked the old project I used an Attiny85 for and I connected the reset pin directly to +. No idea if that was good or not, but it seems to work fine.
It's fine of course, the idea of using a pullup is that you can pull it LOW with a switch or something. That way if you expose the other connections, you can leave the chip on the board for a new upload.
I guess the answer here is "I don't know." I built a programmer using a Nano, which then allows me to upload my Arduino sketch to the ATTiny85, and it just works. I don't remember selecting a core during that process.