This follows a similar key to the Official Name Pronunciation Guide used over at Smogon, but for easy reference:
PRONUNCIATION KEY:
All caps = emphasis
Separated by syllable
A lone vowel means pronounce its short-sound (ex, “i” means like in “it” instead of like “pie”)
Two like-vowels together means the long sound (ex, “ee” means like in “leaf” instead of “meh”)
The difference between G and J: if I put a G, it’s like “gray”; if I put a J, it’s like “jam”

RMNmons
Toribush = TOR – ee – bush
Javelbush = JAV – uhl – bush
Joubush = JOW – bush
Flaregon = FLAIR - gon
Seargon = SEER - gon
Dragablo = drag – AH -blow
Fairimp = FAIR - imp
Siremp = SAHY (like “sigh”) - rimp
Serempity = suh – REMP – I -tee
Atmana = at – MAN - ah
Hydroka = hi-DROH-kuh
Flamesoul = FLEYM (like “flame”)-sohl
Junipervan = joo – nuh – PERV - an
Lectrei = LECK-trey
Gustling = GUHST-ling
Swantweet = SWON-tweet
Miceberg = MAHYS (“ahys” makes an “ice” sound, or in this case, “mice”)-burg
Volice = VOHL-ahys (see above)
Curvri = KUR-vree
Curveat = KUR-vee-aht (weren’t expecting this one, were you?)
Basherp = ba - SHURP
Bassacre = BAS – uh - kur
Quober = KWOH - bur
Quodash = KWOH-dash
Zapasp = ZAP-asp
Venohm = VEN – ohm (It’s seriously like “venom”)
Mycelite = MAHY-see-lahyt
Alampita= ah-lam-PEE-tah
Sespirit (Female)= SEES-pir-it
Sespirita = sees-PIR-it-ah
Darspirita = dars-PIR-it-ah
Sespirit (Male) = …
Sespirito = sees-PIR-it-oh
Claspirito = klahs-PIR-it-oh
Phim = fim (easy…)
Meryphim = MAYR-ee-fim
Marubim = mayr (like "mare")-UH-bim
Chibiwawa = chee-bee-WA-wa
Chi-Nun = chee-NUHN
Chi-Yim = chee-YEEM
Digloch = DIG-lock
Excaloch = EKS-kuh-lock
Tomamer = tuh-MEYM-er
Tomamight = tuh-MEY-mahyt
Flauret = FLAWR-et
Flaurum = FLAWR-uhm
Skrewpent = SKROO-pent
Seradder = ser-AD-er
Demine = DEE-mahyn (like “mine”)
Diablode = dee-AH-blohd
Eelinkk = EEL - ingk
Zaorrior= ZOR-ee-er
Limbatent =lim-BAT-nt
Pozitron =POZ-i-tron
Bulvine = BOOL-vahyn
Biseed = BI-seed (easy)
Catlyx = CAT-licks
Troxin = TROCKS-in
Zhilong = ZAHY-long
Codjestic = kod-JEST-ick
Lushung = luhsh-UHNG
Nasorsal = nah-SOORS-el
Heatha = HEH(like “eh”)-thuh
Heatherain = HETH-er-eyn (think “rain” or “pain”)
Heaven = HEV-uhn (real complicated this one was…)
Afropup = AF-roh-puhp
Afrorunt = AF-roh-ruhnt
Funkound = FUHNK-ownd (like “pound”)
Fuzard = FYOO-zerd
Echeel =eh-KEEL
Ascape = ah-SKEYP
Irritormen = ir-i-TOR-men
Tikny = TEEK-nee
Tikurai = TEE-kur-rahy
Joban = jo-BAN
Kelaylee = kuh-LEY-lee
Shredax = SHRED-aks
Plugla = PLUHG-lah
Totemvolt = TOH-tuhm-vohlt
Inkling = EENGK-leeng
Loblotomy = luh-BLAHT-uh-mee
Bologoo = bohl-AH-goo
Beluga = buhl-OO-guh
Bomara = boh-MAR-uh
Boganna = boh-GAHN-uh
Trunklift = TRUHNK-lift
Libraphant = LEE-bruh-fuhnt
Pyramystic = pir (like “peer”)-uh-MIS-tik
Levitomb = LEV-i-toom
Caltrap = KAHL-trap
Tricalp = TRAHY-kahlp
Akashic = uh-KAH-sheek
Anpsi = AN-sahy (as in “sigh”)
Atavism = AHT-uh-vis-im
Bundulate = BUHN-juh-leyt
Hyppy = HIP-ee
Hypster = HIP-ster
Crabang = kra-BANG
Crabammer = kra-BAM-er
Borc = BORK (insert Swedish Chef joke here)
Borabol = BOR-ah-bul
Gnomkin = NOHM-kin
Dwarkin = DWAWR (just like “dwarf”)-kin
Chellrit = KEEL-rit
Torgheist = TAWR-geyst
Tornment = TAWRN-ment
Ellefan = EL-fan
Acaricide = ak-KAR-i-side
Acylurea =AK-loor-ee-uh
Acarphogus = ak-KAR-foh-gus
Meterain = MEE-tur-ayn
Meterstorm = MEE-tur-stawrm
Maelstorm = MEYL-stawrm
Spiritatue = spir-i-TACH-oo
Megamouth = MEG-uh-mouth
Moryo = MOHR-yoh
Myobu = MYOH-boo
Mantennae = man-TEN-uh
Littlefoot = LIT-uhl-foo t
Bigfoot = BIG-foo t
Nachash = nah-CHAWSH
Ddraig = DRAG
Spitfire = SPIT-fahyuhr
Tonequus = tohn-EH-kwes (similar to “quest” without the “t”)
Equistro = eh-KWES-troh
Ephemin = eh-FEE-min
Ephemeron = eh-FEE-mer-on
Astragon = AS-truh-gon
Mosrock = MAWS-rok
Vegetrol = VEJ-eh-trol
Plantossus = plan-TAHS-us
Dirangers = der-ANG-ers
Batnic = BAT-nik
Raicicle = RAHY-sik-kul
Gyisab = GEE-sahb
Ysuta = YEES-oo-tuh
Muspyg = mus-PEEG
Bitron = BI-trawn
Superbtron = soo-PERB-trawn
Leninja = lee-NEEN-juh
Killerbeat = kil-ER-beet
Vulkanylos = vol-KAN-i-lohs
Pupictya = pew-PIK-tyuh
Demidictya = dem-i-DIK-tyuh
Ripodictya = ree-poh-DIK-tyuh
Byakestial = byah(try to say it as one syllable)-KES-tee-uhl
Suzaestial = soo-ZAYS-tee-uhl
Genbestial = gen (with a “G” like in “Gary”, as oppose to a “j” sound)-BES-tee-uhl
Atardis = ah-TAR-dis
Carvora = car-VAWR-uh
Antipode = AN-ti-pohd