Freshwater Exotics is legit. Ordered from them many times, great fish for great prices, and great customer support and service as well. Shipping can be a bit costly, because they don't do flat-rate, though.
Aqua-Imports is well known for being reasonably reputable.
Pet Zone SD is a real physical storefront, haven't dealt with them myself before, though. Heard mixed reviews.
HappyFishOnline is a bit overpriced IMO and a tad questionable. They're legit, and are willing to work with the customer on matters, but I don't fully trust or like them, especially because they have had some issues with large orders in the past and they market clearly sexually immature fish as sexed pairs.
Paradise Tropicals LLC is legit. Standard WC Brazil import loricariids.
I don't know anything about Aquatic VIP. Seems a bit sketchy, the site, but not too sure.
For L136C, Marcel Wuethrich/Roseline17 on Aquabid and BAND imports some from Germany and also breeds nice-quality fishes.
NelsonRK'd ob BAND used to work with L136B/C, I think; not sure if he still does or not.
Nationwide Aquatics brought in a decent shipment of them a while back as part of a Germany import, he will probably do it again someday.