Following command lists all collations. Even not loaded:

%SYS>do ^COLLATE

E.g.

%SYS>w $zv
IRIS for Windows (x86-64) 2019.1.1 (Build 612U) Mon Oct 28 2019 11:29:24 EDT
%SYS>do ^COLLATE

Status       Number   Abbrev   Name
----------   ------   ------   ----------------------
Built-in        0     OANS     ISM Pre-6.2
Built-in        1     ANSI     ISM 6.2->6.4
Built-in        2     COBR     Ipsum/Cobra
Built-in        3     DTMC     DTM-compatible
Built-in        4     CBR2     Ipsum/Cobra-2
Built-in        5     UNIC     IRIS standard
Not loaded     10     GER1     German1
Not loaded     11     POR1     Portuguese1
Not loaded     12     POL1     Polish1
Not loaded     13     GER2     German2
Not loaded     14     SPA1     Spanish1
Not loaded     15     DAN1     Danish1
Available      16     CYR1     Cyrillic1
Not loaded     17     GRE1     Greek1
Not loaded     18     CZE1     Czech1
Not loaded     19     CZE2     Czech2
Not loaded     20     POR2     Portuguese2
Not loaded     21     FIN1     Finnish1
Not loaded     22     JAP1     Japanese1
Not loaded     24     POL2     Polish2
Not loaded     27     FRE1     French1
Not loaded     28     FIN2     Finnish2
Not loaded     29     HUN1     Hungarian1
Not loaded     30     GER3     German3
Not loaded     31     POL3     Polish3
Not loaded     32     SPA2     Spanish2
Not loaded     33     DAN2     Danish2
Not loaded     34     GRE2     Greek2
Not loaded     35     FIN3     Finnish3
Not loaded     36     LIT1     Lithuanian1
Available      37     CYR3     Cyrillic3
Not loaded     38     SLO1     Slovenian1
Not loaded     39     SLO2     Slovenian2
Not loaded     40     TUR1     Turkish1
Not loaded     41     DAN3     Danish3
Available      42     UKR1     Ukrainian1
Available      43     CYR4     Cyrillic4
Not loaded     44     CZE3     Czech3
Not loaded     46     MAL1     Maltese1
Not loaded     48     MAL2     Maltese2
Not loaded     49     SPA4     Spanish4
Not loaded     50     SLO1     Slovak1
Not loaded     51     SPA5     Spanish5
Not loaded     52     FIN4     Finnish4
Not loaded     53     CZE4     Czech4
Not loaded     54     GER4     German4
Not loaded     56     FRE2     French2
Not loaded     57     GER5     German5
Not loaded     58     NOR1     Norwegian1
Built-in      128     OSTR     ISM Pre-6.2 string
Built-in      129     NSTR     ISM 6.2->6.4 string
Built-in      133     USTR     IRIS standard string
Available     144     CYR1S    Cyrillic1 string
Available     165     CYR3S    Cyrillic3 string
Available     170     UKR1S    Ukrainian1 string
Available     171     CYR4S    Cyrillic4 string