A cotton ball can cover the hole well. While it's actively fermenting you only really need to worry about fly's etc, getting in. Once that slows down and there isn't CO2 protecting your wine then you need the airlock.
Currently not in a bottle: Plum - Shitaki - Hibiscus and mint -Blueberry - Blueberry Pomegranate
Waiting in the bottle: Rose petal / Nasturtium wine - Pomegranate Absinthe - Orange - Rosemary flower and Carrot green wine - (Green)Pu-er Tea wine