Do you know major SAP ISU Tables?

Business Master data:

EKUN = ISU business partner data
BUT050 = Business partner relationships
BUT100 = Business partner roles
BUT020 = Business partner address
ADRC = Addresses
BUT000 = Business partner
DFKKLOCKS = Business locks
FKKVKP = Contract account for partner
FKKVK = Contract account

Billing and invoicing:

ERDK = Print doc header
ERDO = Outsorting for invoices
ERDB = CA document for print document
ERCHO = Outsorting for billing document
ERCHC = Invoicing reversal history
ERCH = Billing doc header
DBERCHZ(1-8) = Billing doc lines
DBERDL = Print doc lines
DBERDLB = Billing doc-print doc line reference

Billing master data:

ETTA = Rate category
ETTAF = Rate category facts
TE221 = Operands
ETRF = Rates
EKDI = Rate facts
ESCHS = Billing schema steps
ESCHS = Billing schema header
EPREIH = Price history
EPREI = Prices header
TE069 = Rate types
ETTIF/ETTIFN/ETTIFB = Installation facts
ERTFND = Rate determination

Technical master data:

EANL = Installation
EVBS = Premise
EHAUISU = Connection object
EANLH = Installation time slice
EGPLTX = Device locations
EUI HEAD = PoDs
EUITRANS = PoD internal to external Ids

Device Management:

ETDZ = Registers
EPROFASS = Registers-profiles
EASTI = Register relationships
EUILZW = Register- Pod
EASTS = Installation-register
EADZ = Multiple installation billing data registers
EZWD = Register Groups
EZUZ = Device allocation for registers
EGERH = Historical device data
EGERS = master device data
EGERR = Device info for Pod
EUILNR = Device Pod
ETYP = Device category- material data
EZUG = Device allocation for device

Scheduling:

TE422 = Meter reading units
TE418 = Schedule records- meter reading units
TE420 = Portions
TE419 = Parameter records
TE417 = Schedule records for portion
ETRG = Billing orders
EABL = Meter reading document
EABLG = Meter reading reasons 

FICA:

DFKKOP = Items in contract account document

DFKKKO = Header Data in Open Item Accounting Document

DFKKOPK = GL Items in contract account document

DPAYH = Payment Run

DFKKZP = Payment lot

DFKKRP = Return lot

FKKMAKO = Dunning

FKK_SEC = Security deposit

FKK_INSTPLN_HIST = Installment plan

DFKKWOH = Write-off history

DFKKLOCKS = FI-CA Business Locks

DFKKCOLL = Submit to collection agency

DFKKCOLLH = History of collection