Hi OP, if you're wanting to conceal pores I'm not sure concealer is a good gambit as I find that the heavier ones, especially, can draw more attention to them. You might be better off addressing them at a skincare level - with a pore minimising serum, or perhaps one of those blurring primers.
I've had good success with the Clinique smart serum, although I know some people have broken out from it. They also do one specifically for pore issues which I like. There are sellers on ebay who sell the "not for resale" samples of the serum in the sachets so you can try before you commit to buying the bottled version, but bear in mind that it takes a while to see results. But the samples will at least allow you to see whether you have a reaction to the ingredients.
If you do decide a concealer is the way to go I second the clarins one for density, but find the Charlotte Tilbury retoucher a nicer texture and better on areas like under the eyes. If you're feeling spendy, the By Terry concealers are second to none.
There's also an application technique to blurring pores with make-up (specifically foundation type products), which is to buff product "into" the pores in a circular motion, first clockwise, then anti-clockwise which has a blurring effect. HTH!