Farming and Tools
This is a fairly arbitrary collection of charges that I think are tools and are often to do with farming.
Farm Related Items
Corn sheaf, spoked-wheel, horseshoe, beehive
The corn sheaf is also known as a garb
Tools and related Items
Anvil, brey, compass, fleam, hammer, forge hammer, hemp-break, key, ladder, millrind, padlock, pair of keys, scythe, artists brush, quill pen
Features and Modifiers
Are not typical for this kind of charge, but the brey may be open, closed.
There is a suprisingly large number of knots used as Heraldic charges, which only the most pedantic can tell apart. DrawShield provides two knots, the celtic knot and a generic knot which is used in all other cases.