Does anyone have a list of fair reliable ETF that follow well their underlying.
For example, $SPY and S&P500, $GLD for Gold, but not $UNG for NatGas.
I would like to start long term portfolio (short and long positions).
Thanks in advance.

from a brief look I don't know if you are going to find a 1 x 1 correspondence that you find with $SPY and the SP500 index

However here is a list of the many many sector based ETFS, not just the top ten as it says in the URL description

Top 10 Sector (General) ETFs

then what you do is simply take a charting service like BigCharts.com and make a comparison

here is an example with the Pharmaceutical sector

Dow Jones U.S. Pharmaceuticals Index, DJUSPR Advanced Chart - (DJI) DJUSPR, Dow Jones U.S. Pharmaceuticals Index Stock Price - BigCharts.com

DRG and DJUSPR Are two different Pharmaceutical indices and the rest are EFT's....they do not overlay the index charts but most follow them pretty close and you can pick the one you want to follow.

this is how I would do your research....pick a sector...then comb through identifying ETF's that seem to follow that index

this page helps you find ETF's for a particular sector...I did not find one for Pharmaceuticals in that list

ETFdb Categories | ETF Database

Hope this helps in your research

Underexposed 

from a brief look I don't know if you are going to find a 1 x 1 correspondence that you find with $SPY and the SP500 index However here is a list of the many many sector based ETFS, not just the top ten as it says in the URL description Top 10 Sector (General) ETFs then what you do is simply take a charting service like BigCharts.com and make a comparison here is an example with the Pharmaceutical sector Dow Jones U.S. Pharmaceuticals Index, DJUSPR Advanced Chart - (DJI) DJUSPR, Dow Jones U.S. Pharmaceuticals Index Stock Price - BigCharts.com DRG and DJUSPR Are two different Pharmaceutical indices and the rest are EFT's....they do not overlay the index charts but most follow them pretty close and you can pick the one you want to follow. this is how I would do your research....pick a sector...then comb through identifying ETF's that seem to follow that index this page helps you find ETF's for a particular sector...I did not find one for Pharmaceuticals in that list ETFdb Categories | ETF Database Hope this helps in your research

I don't think the subjectivity in compare charts visually is needed; just look at the tracking error (an explanation from Vanguard can be found here).

MyTraderAdvisor, I would look at the three (or more) most liquid ETFs for the assets you want to trade, and compare these on various metrics (such as tracking error, costs, bid/ask spread, type of replication, etc) to look for the ones best suited to your goals.

Jura 

I don't think the subjectivity in compare charts visually is needed; just look at the tracking error (an explanation from Vanguard can be found here). MyTraderAdvisor, I would look at the three (or more) most liquid ETFs for the assets you want to trade, and compare these on various metrics (such as tracking error, costs, bid/ask spread, type of replication, etc) to look for the ones best suited to your goals.

That is fine...each of us has their own way of analysis. That site that lists all possible ETF's for each sector should help you in your endeavors...good luck