It is not so often lately that there is a new app and concept making an appearance. This looks like one. Have not tried it and am slightly skeptic as it seems more focused on the visual side of things but I could be wrong and it would have been good if they had a demo to try before as it is kind of expensive compared to other android apps.
But they do state that there will be a reduced free version soon.

Google Play:

Mazetools Soniface

EXPLORATION & EXPRESSION
With Mazetools: Soniface you can create various styles of electronic music. Everything based on common aspects of notation and music production. The in-app manual guides you towards a visual music experience.

HOW THE GRID WORKS?
The framework of action is a grid. Each line represents a single note. Shining lines are showing playing tones. 

X-Y CONTROLLERS & MULTI-TOUCH
Use multi-touch gestures for altering sound effects or explore the circular editing interface.

DYNAMIC SOUND MODULATION
Merge sounds and geometric shapes! Draw sound waves and automation curves freely with your finger to modify the sound effects.

GROOVE SEQUENCER
Just tap into the circle to set bass drum, snare and hi-hat steps. Easily adjust envelopes and pitch levels.

RHYTHMICAL MELODIES
Let the grid play a sequence of notes automatically using the arpeggiator interface.

LIVE MODE & SPECIAL VISUALS
Use different patterns to create song variations. Add a special kaleidoscope visual to a pattern as a highlight.

SAVE YOUR CREATIONS
You can store single Mazes, patterns or whole sessions into a set. Add one set into another and extend your playing time.

STAY CURIOUS!
We will bring spaced out updates and a reduced free version soon...

Get more information on:
https://www.mazetools.com/

Do you want to contact us? Visit our company website:
https://ectoplastic.com/WHAT'S NEW- Synthesizer based on an audiovisual grid implying common aspects of notation
- 3 way monophone drum synthesizer with envelope, pitch and noise level control and automation setup
- integrated manual
- unlimited pattern and instrument implementation
- arpeggiator interface, envelope setup & note step sequencer
- special “kaleidoscope” visual to highlight patterns
- full-screen mode
- easy composition playback
- versatile file library

The contest is based on one song that people can remix or rap over. The prices are okay and as always it will give some attention which never hurt.

To read more:
http://songtr.ee/contest/Rap-Battle

Damian have been doing a lot of compositions using the RD4 lately which is nice as it is maybe not the best sounding app but on a tablet the most user friendly groovebox specially when using a tablet. Very easy to reach and manipulate most of the parameters.
But I would say that the best sounding 303 style groovebox is Audiod. It has a sharpness to its sound that cuts through in a good way that is missing from other Android 303's.
When it first came out it was pretty useless as it had some problems but with some updates it is a hidden secret. It has some deep sound shaping functions in one of the sound engines then the 303 plus two drum machines. It also sports one sequencer that works in its own special way etc.
I have written about it before but seeing this video felt the need to mention it again.
It works better on tablet as the it can become a little bit fiddly on a smaller screen. (With fiddly interfaces and small screens I suggest getting a pen...)
Anyway enjoy the video.

I guess this would be the most advanced amp/Fx guitar emulator on Android plus that it works with external USB soundcards for low latency.​

Google info:

Deplike turns your Android device into an easy-to-use Guitar Multi-Effects Processor (stompbox) and electric guitar amp kit.

Features:

★ 10 Electric, 1 Bass, 1 Acoustic Guitar Amp | 12 great sounding Amp simulations ★ 

Dual Recto
JCM800
P-5550
JTM-45
SVT Bass
BassBoy
Fox Ac30
Deplike Acoustic Amp
Deplike Deluxe (free)
Deplike ANRG
Deplike Crafter
Deplike DST (free)

★ 21 Effects Pedals ★

Classic Overdrive
OD 808
MetalHead Distortion
Full Blast Distortion
Dr.Muff Fuzz

1176 Compressor
Noise Gate
Sustainer

Tremolo
Chorus
AutoWah
Flanger
Phaser

Pitch Shifter
Octaver

Delay
Tape Delay

Reverb 
Roads Reverb 

6 band Equalizer EQ

Looper pedal

★ Tuner ★

WORKS ON EVERY GUITAR :)
We created presets that sound great on every guitar. Even if you want to play heavy metal on an old Fender, the sound will still be familiar.

Watch the how to connect video: https://www.youtube.com/watch?v=ZMKfRzusb_Y

And if you still read, let's join the community and learn more about guitar.
https://www.facebook.com/groups/deplike/

Check Deplike-Faq page for further questions; 
http://deplike.com/andrig-faq/

YouTube Channel:
https://www.youtube.com/c/DeplikeSoft

SoundCloud Page for sample sounds: 
https://soundcloud.com/andrigapp

Feel free to share your ideas with us.
Like us on Facebook: https://www.facebook.com/deplikeSoft

Web Site: http://deplike.com

The Best Android Guitar Amp app and Guitar pedals, tools & effects Processor(Guitar Rig), Guitar Pedals App
Android Guitar Rig application.

Deplike is a mobile application that turns your Android device into an electric and bass guitar amplifier (shortly “amp”) kit. Instead of investing in expensive and hard-to-carry amp, electric guitar players can quickly access, affordably purchase, and enjoy using Deplike easily on their mobile devices anywhere with their electric guitars.

Deplike is aiming a high-performance guitar amp, multi-effects processor and stompbox kit simulation.

Requirements:
- Android 4.1 or higher
- A USB Audio Interface* or a 4-pin stereo input cable to activate the device’s microphone feature

*The USB Audio interface must meet these requirements:
- 16-bit Bit-depth
- 48kHz sampling rate
- 1 Input / 1-2 Output channels

Compatible Devices and Cables:

- http://www.amazon.com/Behringer-UCG102-BEHRINGER-GUITAR-LINK/dp/B000PAPO9W/ref=sr_1_1?ie=UTF8&qid=1439559241&sr=8-1&keywords=positive+grid+irig+fender+guitar+amp+guitar+amplitube+line6+overdrive+distortion

- http://www.amazon.com/Griffin-Technology-GuitarConnect-Cable-iPhone/dp/B003VWZJEQ/ref=sr_1_2?ie=UTF8&qid=1408547194&sr=8-2&keywords=irig+fender+guitar+amp+guitar+amplitube+positive+grid+line6+overdrive+distortion

- http://www.ebay.com/itm/IK-Multimedia-iRig-Guitar-Adapter-for-iphone-ipod-ipad-/331228089924?pt=Other_Tablet_eReader_Accessories&hash=item4d1ebb8e44+overdrive+distortion

- http://www.amazon.com/AMPLITUBE-IK-MULTIMEDIA-GUITAR-IPHONE/dp/B003W47NII/ref=sr_1_1?ie=UTF8&qid=1408547194&sr=8-1&keywords=irig+fender+guitar+amp+guitar+ampkit+positive+grid+fender+line6+overdrive+distortion