It depends on the size of your boat and where you anchor.Below I have listed several scenarios that each require the use of different anchors.
Hall anchor

A Hall anchor is a commonly used conventional stockless anchor found throughout the commercial shipping industry. The traditional design and proven performance makes the Hall anchor an attractive anchor for your ship. The Hall anchor is stowed against the shell or frog eye.
Bruce Anchor

The Bruce anchor is an excellent all-purpose anchor as it performs well in most sea bottoms including mud, sand, rock, and coral. It has a harder time penetrating harder surfaces, such as clay, and bottoms with heavy grass. The three-claw design sets more easily than other anchors.
Plough Anchor

Generally speaking, the most versatile anchors are the plough anchor. They will provide good holding in mud, sand and gravel. In large rocks, they can skid around or jam tight.
Fisherman Anchor

The Fisherman anchor holds well on rock and weed, but its tiny flukes are likely to drag on any other bottom, ruling it out in most anchorages. Fishermen anchor where the fish are, over reefs and rocky outcrops.
Danforth Anchor

If space is tight on your boat, a Danforth / flat anchor is good to have. They will provide good holding on soft bottoms until the tide changes. It’s a good second anchor to carry as a kedge.(You’ll really appreciate that kedge anchor when you run aground on a lee shore and are frantically rowing your dinghy seaward to drop an anchor and pull your boat off before the ebb sets in. )
Grapnel Anchor

A folding grapnel anchor is all you need for a dinghy or small runabout, if you just want to take a breather for an hour or two.
Spade Anchor

A spade or Bügel anchor provides a good holding-to-weight ratio and is a rock-solid piece of kit. It’s a nice simple design. Makes a good (possibly better) alternative to a plough.
There are lots of variations on these patterns.
All-Chain Anchor Line Or a Combination Of Chain And Rope

You should also consider whether you want to have an all-chain anchor line or a combination of chain and rope. You should carry rope/chain for at least 10 times the depth of water you’re expecting to anchor in. So if you’re anchoring off coasts which are steep-to, in depths of around 6–8 metres, you will need to attach at least 10 metres of chain and 70 metres of rope to your anchor.
Even for a lunchtime stop in good weather, your anchor ‘scope’ (the amount of line that you pay out) will need to be at least five times the depth of water for even remotely secure holding. An anchor has to be pulling horizontally to set.