Is this possible? Advantage on saving throws against enemy type.

[Legadin]

I was thinking that this would work: IFT: TYPE(fey, undead); ADVSAV

I figured that would grand advantage on saves vs fey and undead as similar works with protection from evil and good:
IFT: TYPE(aberration, celestial, elemental, fey, fiend, undead); GRANTDISATK; IMMUNE: charmed,frightened,possessed; (C)

However perhaps ADVSAV doesn't work in a similar manner?

Any assistance would be appreciated.

[LordEntrails]

I don't think so. Only some effects are targetable (i.e. usable with IFT).
Have you looked at: 5E Effects for Advanced Automation - Fantasy Grounds Customer Portal - Confluence (atlassian.net)

edit: yep, ADVSAV is not targetable. It would have a (T) in the notes column of this table. https://fantasygroundsunity.atlassia...tion#Modifiers

[Legadin]

Ah, I did look through there but when I did I missed this paragraph:

It needs to be noted that not every modifier can be used in this way. Modifiers which can be make use of effect targeting have a ‘T’ in the ‘Notes’ column in the tables below. For convenience these are ATK, AC, DMG, Invisible, RESIST, VULN, IMMUNE, COVER, SCOVER, ADVATK, DISATK, GRANTADVATK, GRANTDISATK.

Aw well, just a minor annoyance. Shame ADVSAV isn't in there but it is what it is. Appreciate such quick assistance LordEntrails!