I assume you meant highpor
n.net (just to make sure that the link works). There are several sites like that, e.g. javfor.me... which seems dead now... Damn, you never expect those thing. Good that I got some of the titles I only found there saved somewhere
(Judging by Wayback Machine, it went down in 2023 or even earlier. I haven't used it for a long time, and now I won't be able to...)
On the upside, I found this
list of similar sites. Also, there are some obscure sites that you might find by searching the original Japanese title. These are not Japanese sites, but the more ways you use to find something (the original title, the "full code" e.g. with all the preceding zeroes and the letter prefix), the higher the probability that you'll find some source that has it