@sheldon.rong, yes there are solutions, and you can go even further than just separating between equity, future and option.

Let me first answer on Asset Category, then list other useful fields, and finally cover the lock you see on some fields.

Asset Category

You can retrieve the list of all code values and corresponding names using:

GET https://hosted.datascopeapi.reuters.com/RestApi/v1/Search/GetAssetCategories

Result for some of those you mention (I could not find the others using this call):

• EIF: Equity/Index Future
• EIO: Equity/Index Option
• EIS: Equity/Index Spread
• EQI: Equity Index
• ORD: Ordinary

The full list can be found on Customer Zone, here (this delivered the 3 others you mention):

• FXF: FX Fixing
• IRF: Interest Rate Future
• IRX: Interest Rate Fixing

Customer Zone requires a login. If you do not have one, contact your account manager.

Other asset classification fields

There are other more appropriate fields you can use. They all contain the word Type. To see them all, in the GUI create a T&C template, go to the Fields tab and enter the word type in the search field:

There is a big choice. Clicking on a field displays a description and a list of possible values. In the screenshot I highlighted the Asset Type field, which seems to fit your need.

There are many fields that could be of interest to classify instruments, as you can see from the screenshot. There are also MiFID specific fields.

Instead of using the GUI, you can also find these fields in the Data Dictionary. In the Excel sheet, tab Field Descriptions, filter column C to contain only Terms and Conditions, and use a text filter on column D to display only those that contain the word Type:

Note that in column C there is a link, it leads to a Customer Zone page that contains a list of possible values.

For Asset Type these are the possible codes, with their description:

ABSY Asset Backed Securities 
AGNC Agency 
BKLN Bank Loan 
BMRK Benchmark 
CDO Collateralized Debt Obligation 
CDS Credit Default Swap 
CMBS Commercial Mortgage-Backed Security 
CMO CMO's 
COMM Commodities 
CORP Corporate 
DERV Derivatives 
EQTY Equities 
GOVT Govt/Treasury/Central Bank 
IRS Interest Rate Swap 
MGEN Mortgage Pass-Thru Generics 
MONY Money Market 
MORT Mortgages 
MTLF Mutual Funds 
MUNI Municipals 
NDSS Non-DSS Security Type 
OMUN Non-US Munis 
OTCS OTC Derivatives and Limited Terms 
OTHR Other Gov/Supra 
SBA Small Business Administration 
SUBC MiFID Sub-Class 
TBA Mortgage Pass-Thru TBA 

Locked fields

In the GUI, if a field displays a lock, is displayed in green or bold, click on it to see what that means. A lock means it is a prohibited field, requiring an additional permission. Contact your account manager if you need additional permissions.

You can check your current access rights here, 3rd party permissions here and broker entitlements here.

@sheldon.rong, I made a test for you, this data sample could help you make your choices.

Postman request with some of the "type" fields:

{
    "ExtractionRequest": {
        "@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.TermsAndConditionsExtractionRequest",
        "ContentFieldNames": [
           "RIC", "Asset Category",
           "Asset Type", "Asset Type Description", "Asset SubType", "Asset SubType Description",
           "Bond Type", "Bond Type Description", "Contract Type", "ETF Type", "FX Type - ESMA",
           "Instrument Type Code", "Instrument Type Code Description"
        ],
        "IdentifierList": {
            "@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.InstrumentIdentifierList",
            "InstrumentIdentifiers": [
                { "Identifier": "00209tab1", "IdentifierType": "Cusip" },
                { "Identifier": "IBM.N", "IdentifierType": "Ric" },
                { "Identifier": "CHF=", "IdentifierType": "Ric" },
                { "Identifier": "B1YW440", "IdentifierType": "Sedol" }
            ]
        }
    }
}

Response:

RIC,Asset Category,Asset Type,Asset Type Description,Asset SubType,Asset SubType Description,Bond Type,Bond Type Description,Contract Type,ETF Type,FX Type - ESMA,Instrument Type Code,Instrument Type Code Description
00209TAB1=RRPS,,CORP,Corporate,CSVC,Services,CORP,Corporate,,,,NT,Note
IBM.N,ORD,EQTY,Equities,ODSH,Ordinary shares,,,,,,,
CHF=,SPO,MONY,Money Market,MONY,Money Market,,,,,,,
LP71000002,,MTLF,Mutual Funds,INVT,Investment Trust,FCLS,,,,,,