http://timesofindia.indiatimes.com/thumb/msid-57373277,width-400,resizemode-4/57373277.jpg

Assets are tokens that are built on top of a parent blockchain (usually one made specifically to allow asset creation).  I decided to look into 15 different assets that live on the Ethereum, Omni, NXT and Counterparty blockchains.  I have listed each asset alphabetically in the table below along with their ticker symbol, parent blockchain, main feature (in my opinion) and the country in which most of the team resides.  Hopefully this will provide a quick overview for those just starting to look into assets.

Asset | Ticker | Blockchain | Main Feature | Country
- | - | - |- | -
Ardor | ARDR | NXT | Child blockchain services | Netherlands
Augur | REP | Ethereum | Market prediction platform | USA 
Bitcrystals | BCY | Counterparty | Gaming token | Switzerland
DigixDAO | DGD | Ethereum | Backed by gold bars | Singapore
Gnosis | GNO | Ethereum | Market prediction platform | USA
Golem | GNT | Ethereum | Distributed computing | Poland 
Iconomi | ICN | Ethereum | Asset investment management | Slovenia 
iExec | RLC | Ethereum | Distributed computing | France
Lunyr | LUN | Ethereum | Knowledge base | USA
MaidSafeCoin | MAID | Omni | Distributed storage | Scotland
StorjcoinX | SJCX | Counterparty | Distributed storage | USA
Synereo | AMP | Omni | Social networking | Israel
Tether | USDT | Omni | Mainly a currency | China
vSlice | VSL | Ethereum | Gaming token | USA 
Wings | WINGS | Ethereum | Autonomous organizations | Russia

I advise you to go explore each asset in more depth.  The main features that I listed are usually just a part of what makes each one unique.  This simple breakdown does not do these assets justice.

For more information about any of these assets, they are all listed near the top of https://coinmarketcap.com/assets/  (currently the best website to start your research for any cryptocurrency or asset!)