I'd say Lazarsfeld's book "Positivity in algebraic geometry I,IIPositivity in algebraic geometry I,II" is the standard reference these days. In particular, Volume I has a lot of explicit examples. I also recommend Debarre's book 'Higher dimensional algebraic geometry"'Higher dimensional algebraic geometry" which is similar in style with a lot of nice examples and explicit computations.
If you are familiar with toric geometry, there is (not surprisingly) a simple description of the psedudoeffective cone in terms of the combinatorial data in the fan. See Cox-Little-Schenck's new book 'Toric varieties''Toric varieties' for details. This gives a hoard of interesting examples.
Example. Let $X$ be the blow-up of $\mathbb{P}^2$ at two points and let $E_1,E_2$ be the exceptional divisors. A basis for $Pic(X)$ is given by $L,E_1,E_2$ where $L$ is the pull back of a general line in $\mathbb{P}^2$. We show that $\overline{Eff}(X)$ is spanned by $E_1,E_2$ and the strict transform of the line $L_0=L-E_1-E_2$. Let $\tau$ be the cone spanned by these three classes. Since they are all effective we have $\tau\subset \overline{Eff}(X)$. CoverselyConversely, let $D$ be any effective divisor with class $aL+bE_1+cE_2$. We will show that $D$ can be written as a sum of elements from $\tau$. We may assume $D$ to be irreducible. If $D$ is not one of the $E_1,E_2,L_0$, we then have $D.E_i\ge 0$ and $D.L_0\ge 0$. In particular, $D$ belongs to the dual cone of $\tau$, which is easily computed as $\tau^*=\langle L,L-E_1,L-E_2\rangle_{\ge 0}$. Now $L, L-E_1, L-E_2$ are all effective and can be written as positive linear combinations of $E_1,E_2,L_0$, and hence so can $D$. As a by-product, we have just computed the nef cone, which is $\tau^\*$$\tau^*$.
B. Harbourne "Global aspects of the geometry of surfaces""Global aspects of the geometry of surfaces" and
Y. Tschikel "Algebraic varieties with many rational pointsAlgebraic varieties with many rational points.
For K3 surfaces, S. Kovacs has a nice paper on the 'Cone of curves of a K3 surface''Cone of curves of a K3 surface' (see also this answerthis answer). There are also many explicit examples in Artebani-Hausen-Laface's paper On Cox rings of K3-surfacesOn Cox rings of K3-surfaces.
I can also recommend Artie Prendergast-Smith's papers at his homepagehis homepage. In particular, his PhD thesis contains a very explicit example where he computes the of the effective cone of a rational threefold.
A. Laface, M. Velasco, A survey on Cox ringsA survey on Cox rings
I. Arzhantsev, U. Derenthal, J. Hausen, A. Laface, Cox ringsCox rings
J. Gonzalez, M. Hering, S. Payne, H. Süß Cox rings and pseudoeffective cones of projectivized toric vector bundlesCox rings and pseudoeffective cones of projectivized toric vector bundles and
M. Artebani, A. Laface Cox rings of surfaces and the anticanonical Iitaka dimensionCox rings of surfaces and the anticanonical Iitaka dimension