Is there any kind of liquor neutral enough to make different flavours of ice cream, like vanilla or fruit flavours? I've used amaretto for coffee which is divine, but will probably taste too strong for other flavours.
Most liqueurs have an underlying flavour that comes from the ingredients used to make the alcohol and these underlying flavours can be used to enhance or compliment the flavour of some of the no-churn ice creams. Liquers are also added to the ice creams as the small amounts of alcohol can help the texture of the ice cream - stopping it from freezing too solidly and making it easier to scoop.
Most of the no-churn ice creams can also be made without the added alcohol. Particularly the ones made with condensed milk, such as Nigella's One-Step No-Churn Coffee Ice Cream (from Nigellissima and on the Nigella website). If you do want to add a neutral liquor then vodka is generally seen as the most neutral alcohol in terms of flavour, or a vanilla flavoured vodka would go very well with most ice cream varieties.