Thankfully the essential decorators toolkit is not as wide-ranging as others, unless of course you include ladders, steps and the like! You’ll want a couple of filling knifes, or scrapers as most people call them. A thin one for opening up cracks and smoothing off filler and a bigger one for scraping off wall paper.
Dust sheets are a must too. They come in a variety of materials and sizes and are used to cover furniture and flooring. For infrequent use there are plastic disposable ones or if you foresee a regular need then lightweight cotton or heavyweight canvas sheets are available.
The regular toolbox staples of hammer and screwdrivers also have their place in a decorators tool set. You’ll often need to remove shelves and electrical fittings whilst decorating, and of course put them back, so a good selection of screwdrivers is necessary. A claw hammer will make easy work of removing nails and rawlplugs and can help to gently persuade loose patches of plaster to disappear from the wall.
A good sharp knife should always be on hand for open packets and trimming wallpaper to size along with a tape measure for working out how much paint or wall covering is needed.
A selection of good quality paint brushes is essential, from half an inch up to four inches should cover most eventualities. It is worth noting at this point that good quality paint brushes do not come in a set for 2.99 or less. If your also going to be hanging wallpaper then you will need a bucket, a paste brush and a paper hanging brush to to get rid of those pesky bubbles, although some prefer to use a squeegee or even a dry clean paint roller..
A long with a set of brushes you’ll probably be wanting a roller and tray. Nine inch wide roller cage and cover is an ideal size for most emulsioning jobs, add a mini roller for reaching behind radiators and for small touch up jobs and you should be good to go painting wise.
As most flexible fillers and sealants are today supplied in cartridges you’ll need a caulk gun, avoid the plastic ones, the metal ones cost only slightly more. Any one who has ever dropped a full tin of paint from a ladder will confirm that a paint kettle is a great buy! Available in plastic or metal, decant a small amount of paint into it, lighter and easy to hold it also avoids paint from skinning one when left open for a long time. Try picking up a cheap ladle too, much cleaner than just pouring from the tin.
The above items are all the essentials but you may want to add a plumb line for hanging the first piece of wall paper nice and straight, a cork sanding block and although not strictly a toolbox item, a pasting table. A spirit level for making sure dado rail, mouldings and shelves go up level, a pencil and one more thing that I would personally include in the essentials list, a radio.