Popular malware seen in 2018, I have uploaded APK files for all the entries that I could on my Github repository
January
Adultswine - Porn masquerading children apps
SkygoFree - Android spy
GhostTeam - Facebook credentials stealer and adware
Kotlin malware - First malware in Kotlin language
Dark Caracal - Cyber espionage campaign
ExoBot - Bank overlay
February
Adb miner - Monero miner worm
Drive-by Android cryptominer - The cryptomining menace continues
AndroRAT - Updates to AndroRAT
March
RedDrop - A new Android spyware
Ahmyth RAT - Yet another Android RAT
HenBox - Masquerades a variety of legit apps
RottenSys - Mobile adware and a possible botnet
Fakebank - Intercepts calls which connect to banks
QR malware - Malware in QR reading utilities
April
HiddenMiner - Another monero miner
Kev Droid - Fake AV
Roaming Mantis - OTP stealer/banker
May
ZooPark - MiddleEast targeted campaign
Stealth Mango - Pakistan targeted campaign
Timer malware - Waits for a time duration before causing infection
Pre-installed malware - malware hidden in the device before it is sold
June
MysteryBot - A new banking trojan
Telegram Rat - Abuses Telegram for its communication
Fortnite - Scam for the popular game
HeroRat - Remote access Trojan
TV miner - Miner infects Android TV sticks
Emulator miner - Miner infects Android emulators
Telegram RAT - Malware RAT spreading via Telegram
July
Lipizzan - Spyware linked to cyberarms
Anubis - Android Banker malware
Miner ban - Google takes hard steps to ban miners
Exobot leak - Source code leaks
Twisted SDLC - Malware with windows executable files
August
Triout - Spyware framework with extensive survaillence
Tarambuka - Long running spyware is still active
September
Black Rose - A complex Malware-as-a-Service campaign
FBot - A vigilante malware that removes crypto malware from infected devices
OwnMe - Spyware that steals WhatsApp data
October
Gplayed - Customizable Android trojan
Fortnite crypto - Crypto Miner
Panini Adware - Consumes a lot of network data to display ads
TimpDoor - Creates a hidden proxy
November
MaliciousDev - Apps from a malicious dev
December
ClickFraud - Malware changes the User-Agent for get more profit
PaypalStealer - Steals money from PayPal accounts
Dew18 - Banker targets Korean financial institutions