Its very easy task but you should remember that you cannot delete viber stickers because they are downloaded but you can ON, OFF your viber stickers according to your choice. After doing this you will see only selected stickers.
Firstly open your Viber App like this
Now go to messages and click on message space as you want to write something.
Then click on sticker option like this
Now stickers will open up. Click on bottom left "+" icon to add more stickers.
By doing this you can go to stickers settings.
Now sticker market will open up. Click on top right option to go to sticker settings like this
Now you can see all stickers categories are marked as ON.
Now OFF sticker categories according to your choice.