There are numerous financial institutions that provide ETF. They are:
Barclays Global Inv
State Street Global
Vanguard Group
Clifton Group
Credit Suisse
Evergreen Investments
Merrill Lynch
Fidelity Investments
Todd Investment
Bank of New York
List of ETF: Barclays Global Inv: iShare ETFs
EFA: iShares MSCI EAFE Index Fund
EEM: iShares MSCI Emerging Index Fu
IVV: iShares S&P 500 Index Fund
TIP: iShares Lehman TIPS Bond Fund
LQD: iShares GS $ InvesTopTM Corpor
FXI:iShares FTSE/Xinhua China 25 I
IWM: iShares Russell 2000
AGG: iShares Lehman Aggregate
IWF: iShares Russell 1000 Growth
EWZ:iShares MSCI Brazil Index Fund
IWD: iShares Russell 1000 Value
SHY: iShares S&P/Citigroup 1-3 Year
EWJ: iShares MSCI Japan Index Fund
IVW: iShares S&P 500 Growth Index F
IJH: iShares S&P MidCap 400 Index F
IWB: iShares Russell 1000
DVY: iShares Dow Jones Select Divid
IJR: iShares S&P SmallCap 600 Index
SLV: iShares Silver Trust
IWR: iShares Russell Midcap Index F
HYG: iShares iBoxx $ HY Corp Bond F
IWN: iShares Russell 2000 Value
EWT: iShares MSCI Taiwan Index Fund
IVE: iShares S&P 500 Value Index Fu
IWO: iShares Russell 2000 Growth
List of ETF: State Street Global: SPDR ETFs
SPY: SPDR S&P 500
GLD: SPDR Gold Trust
MDY: SPDR MidCap Trust Series I
DIA: Diamonds
XLE: SPDR Select Sector Fund – Energy sector
XLK: SPDR Select Sector Fund - Tech
JNK: SPDR Lehman High Yield Bond ET
XLU: SPDR Select Sector Fund - Utilities
XLV: SPDR Select Sector Fund - Heal
XLP: PDR Select Sector Fund - Cons
BWX: SPDR Lehman Intl Treasury Bd
XLI: PDR Select Sector Fund - Industrial
BIL: SPDR Lehman 1-3 Month T-Bill E
XLF: SPDR Select Sector Fund - Financial
XLB: SPDR Select Sector Fund - Basic
KBE: SPDR KBW Bank ETF
XLY: SPDR Select Sector Fund
RWX: SPDR DJ Wilshire Intl Real Estate
TFI: SPDR Lehman Municipal Bond
SHM: SPDR Lehman Short Term Municipal
RWR: SPDR DJ Wilshire REIT ETF
XRT: SPDR S&P Retail ETF
WIP: SPDR DB International Government
GXC: SPDR S&P China ETF
GM: SPDR S&P Emerging Asia Pacific
List of ETF: Vanguard Group
VTI: Vanguard Total Stock Market ET
VWO: Vanguard Emerging Markets ETF
BND: Vanguard Total Bond Market ETF
VUG: Vanguard Growth ETF - DNQ
VEU: Vanguard FTSE All World Ex US
VEA: Vanguard Europe Pacific
VTV: Vanguard Value ETF - DNQ
VNQ: Vanguard REIT ETF - DNQ
VV: Vanguard Large-Cap ETF - DNQ
BSV: Vanguard Short-Term Bond ETF
VGK: Vanguard European ETF
VB: Vanguard Small-Cap ETF - DNQ
VO: Vanguard Mid-Cap ETF - DNQ
VPL: Vanguard Pacific ETF
VIG: Vanguard Div Appreciation ETF
VBR: Vanguard Small-Cap Value ETF
VBK: Vanguard Small-Cap Growth ETF
BIV: Vanguard Intermediate-Term Bon
VDE: Vanguard Energy ETF
VXF: Vanguard Extended Market ETF
VOT: Vanguard Mid-Cap Growth ETF
VGT: Vanguard Information Tech ETF
VOE: Vanguard Mid-Cap Value ETF – D
VHT: Vanguard Health Care ETF - DNQ
VDC: Vanguard Consumer Staples ETF
List of ETF: Merrill Lynch
OIH: HOLDRS Merrill Lynch Market Oil
PPH: HOLDRS Merrill Lynch Pharmaceutical
SMH: HOLDRS Merrill Lynch Semiconductor
BBH: HOLDRS Biotech
RTH: HOLDRS Merrill Lynch Retail
HHH:HOLDRS Internet
UTH: HOLDRS Merrill Lynch Utilities
RKH: HOLDRS Merrill Lynch Regional
TTH: OLDRS Merrill Lynch Telecom
SWH: HOLDRS Merrill Lynch Software
BDH: HOLDRS Broadband
IAH: HOLDRS Internet Architecture
WMH: HOLDRS Merrill Lynch Wireless
MKH: HOLDRS Market 2000+
IIH: HOLDRS Internet Infrastructure
EKH: HOLDRS Europe 2001
BHH: HOLDRS B2B Internet
The lists of ETFs mentioned above are based on the volume of the respective market cap.