Well, DHB is the Alpha 5 reduced form of boldenone. NPP is a Nortesterone 19 derivative. there are three broad categories of AAS:
- DHT (Dehydrotestone, A-drol, Winny, Primo, Masteron...this is where DHB fits in) These have zero estrogenic effect as they can not be converted by Aromatase. Clean keepable muscle building and (Exception: A-drol bonds to estrogen receptors for some odd reason)
- Nortestosterone (Deca, NPP, Tren) mild conversion to estrogen or as Tren zero, but Progestenic, Deca/NPP can cause mild bloating and lubes joints. Tren burns fat and can increase apatite as well as nutrient partitioning
- Testosterone derivatives (Testosterone itself, D-bol) can convert to estrogen fairly easy but the gold standard and most used of AAS
So, I myself never take any AAS without some testosterone as, the body converts it into a whole cascade of metabolites needed. Deca/NPP are more anabolic than testosterone but should never be run solo. Any form of DHT, if you watch your sodium, will yield clean gains and preserve muscle on a calorie restricted diet.
To your question, IMHO, I'd never run anything without at least a low dose of test. Deca/NPP are a versatile pair, good for cutting or bulking support (remember lubed joints are handy for pushing heavier weights). DHTs (DHB) compliment any cycle variation too but are most often used for cutting/muscle fiber maintenance.
Both compound are amazing but shear muscle gain...NPP
If you want clean mass and looking ripped, dry muscles - Test/DHB
If you want more mass and don't mind a little extra water - Test/NPP
To tweak that add in both DHB and NPP to your test. If its you first 2-3 cycles consider test only and find your sweet spot there. Do some research to ensure your health, PCT and such as any AAS will crash your natty test.